haworth, 2003 rmc 2003

RMC 2003

JUNE 15-18, 2003

UNIVERSITY OF MISSOURI

Proceedings of the

56th Reciprocal

Meat Conference

The American Meat Science Association is a non-profit scientific professional society for individuals working in the field of meat science. AMSA is a broad-reaching organization of individuals that develops and disseminates its collective food and animal science knowledge to provide meat science education and professional development. AMSA’s annual Reciprocal Meat Conference is the leading venue for networking and information exchange among researchers in academia, industry and government. For more information on AMSA programs and services, go to http://www.meatscience.org. American Meat Science Association 1111 N Dunlap Ave Savoy, IL 61874 Phone: (217) 356-5368 Fax: (204) 465-0688 Email: [email protected] A complete catalog of titles is available on the AMSA home page at http://www.meatscience.org Copyright © 2003 by the American Meat Science Association Permission to reproduce or transmit in any form or by any means, electronic or mechanical, including photocopying and recording, or by an information and storage and retrieval system, must be obtained in writing from the publisher at the address or fax number above.

2002-2003 American Meat Science Association

Board of Directors

OFFICERS

President Joseph G. Sebranek Iowa State University

President Elect Craig D. Bacon Tyson Foods

Past President Jeff W. Savell Texas A&M University Secretary Treasurer C. Ann Hollingsworth Better Built Foods

DIRECTORS

Elizabeth A. E. Boyle Kansas State University

Casey Frye Burke Corporation

RMC Chair Dan S. Hale Texas A&M University

D. Dwain Johnson University of Florida

Collette M. Schultz Kaster Premium Standard Farms

Wesley N. Osburn Michigan State University

EXECUTIVE DIRECTOR Thomas H. Powell American Meat Science Association

55th Annual Reciprocal Meat Conference i

2003 Committees of the American Meat Science Association

2005 ICoMST Organiz-ing Committee R. B. Sleeth S. H. Richert D. B. Anderson A. M. Booren L. L. Borchert C. R. Calkins R. G. Cassens L. R. Graves Delmore L. C. Faustman S. J. Goll C. A. Hollingsworth M. C. Hunt H. K. Johnson J. T. Keeton M. Koohmaraie N. G. Marriott K. W. McMillin D. J. Meisinger J. G. Sebranek J. N. Sofos M. B. Solomon

Achievement Award E. J. Huff-Lonergan S. Barbut D. H. Beermann D. C. Beitz K. L. Kotula W.G. Moody

Archives/Historical D. H. Kropf T. R. Dockerty K. J. Fromme C. L. Knipe

Auditing C. L. Kastner W. R. Henning M. L. Kreul T. J. Rourke

Budget C. A. Hollingsworth R. J. Delmore D. J. Meisinger L. C. Faustman

Continuing Education D. B. Griffin E. P. Berg D. E. Burson C. R. Calkins J. G. Gentry N. G. Marriott D. M. Wulf

Educational Materials M. L. Rossman P. T. Berg J. C. Forrest R. M. Harp J. M. Hochstetler J. M. Leheska L. E. Mease R. A. Nold A. E. Reynolds

Emeritus Membership D. M. Allen J. A. Boles Z. L. Carpenter T. R. Dockerty L. E. Orme R. Steiner

Extension-Industry Ser-vice Award D. B. Burson D. T. Bartholomew E. A. E. Boyle R. C. Johnson M. E. O'Connor W.C. Schwartz

Foundation Trustees R. B. Sleeth L. L. Borchert J. J. Harris H. K. Johnson C. L. Kastner D. J. Meisinger W. G. Moody

Graduate Poster Compe-tition T. D. Pringle A. L. Alderton E. P. Berg J. A. Boles K. B. Chin S. J. Eilert R. M. Harp G. J. Hausman M. F. Miller B. Paterson W. Pinkerton

Intercollegiate Meat Coaches Executive Board H. G. Dolezal, President C. D. Alexander T. R. Carr K. B. Bullock R. C. Hines W. B. Mikel J. B. Morgan

International Award W. R. Usborne J. C. Acton H. R. Cross E. Puolanne M. H. Stromer G. K. Williams J. B. Wilson

International J. W. Cravens R. P. Clayton D. J. Hanson E. J. Huff-Lonergan W. R. Lloyd M. K. McMindes T. H. Montgomery E. Puolanne K. K. Scheller D. L. Seman W. R. Usborne

Long Range Planning S. J. Goll K. D. Childs M. Koohmaraie M. J. Marchello K. W. McMillin M. F. Miller R. K. Miller F. Toldra

Meat Industry Research Conference Planning S. D. Shivas B. L. Gwartney R. W. Jabaay D. D. Johnson R. C. Johnson E. W. Mills A. L. Schroeder G. L. Smith R. Tarte

Meat Processing Award A. M. Booren D. L. Engeljohn R. W. Jabaay M. T. Lesiak R. E. Rust P. J. Shand

Newsletter M. L. Scaggs B. Booren C. Grimes M. Hardin R. J. Maddock K. W. McMillin W. B. Mikel C. Quinlan M. Sutton-Vermeulen J. W. Wise

ii American Meat Science Association

Nominations J. W. Savell J. C. Acton H. R. Cross L. W. Hand R. A. Hendricks K. Mastracchio L. R. Miller

Parliamentary G. Schmidt D. W. Henderson T. D. Schnell

Processed Meats Clinic R. Tarte J. Bohac R. S. Miles P. O’Connor B. K. Quandt J. R. Ransom W. C. Schwartz

Professional Membership T. H. Montgomery E. Boyd R. G. Cassens D. L. Engeljohn L. E. Jeremiah S. L. Martin E. S. Troutt

RMC Exhibits & Table Tops D. T. Bartholomew A. D. Clarke T. H. Montgomery

RMC Program D. S. Hale D. R. Buege C. M. Calhoun S. J. Eilert L. C. Faustman M. Koohmaraie C. L. Lorenzen E. L. Rubendall J. N. Sofos T. L. Wheeler Y. L. Xiong H. N. Zerby

Recognition H. K. Johnson D. M. Allen S. G. Campano T. R. Carr J. T. Keeton R. W. Mandigo

Research Award M. B. Solomon S. K. Beals D. R. Campion M. C. Cassens T. A. Houser E. J. Huff-Lonergan D. K. Larick R. M. Robson

Research Needs Asses-ment S. M. Lonergan M. S. Brewer M. E. Cassens A. W. Kotula C. A. Payne G. R. Skaar A. A. Sosnicki

Research Protocol C. L. Lorenzen S. K. Beals A. M. Booren J. E. Cannon D. E. Carpenter E. A. Decker J. S. Dickson M. E. Doumit J. R. Stouffer

Resolutions & Necrology M. J. Riemann R. W. Rogers J. W. Wise

Scientific Information K. E. Belk M. J. De La Zerda L. R. Graves Delmore S. K. Duckett T. Hively J. H. Hodges M. C. Hunt A. King W. F. Pinkerton A. E. Rasor J. M. Regenstein R. R. Timm N. C. Tipton A. T. Waylan

Student Board J. Leheska J. M. Behrends T. A. Houser C. Quinlan J. R. Ransom J. Stephens A. T. Waylan

Student Membership G. G. Hilton C. L. Armstrong P. K. Bates J. M. Behrends M. A. Carr B. Covington A. King D. McKenna

Sustaining Membership M. S. Franzreb P. W. Hall R. D. Huffman K. L. Kotula M. T. Lesiak

Teaching Award S. J. Jones E. P. Berg J. C. Brooks L. C. Faustman R. M. Harp M. C. Hunt N. G. Marriott F. K. Ray

Undergraduate Scholas-tic Achievement Award J. A. Scanga S. K. Duckett S. D. Harris G. G. Hilton R. C. Person D. M. Roth

Web Site S. J. Jones S. J. Boleman J. R. Claus M. J. De La Zerda C. Jolley J. Sindelar

Western Meat Science Update Conference C. L. Knipe G. A. Barkocy-Gallagher R. J. Delmore R. L. Dickson R. A. Hendricks R. C. Person D. L. Seman

Special Appointments ICoMST Contact Person R. B. Sleeth HACCP Alliance Rep M. C. Hunt Job Board Coordinator E. A. E. Boyle

55th Annual Reciprocal Meat Conference iii

American Meat Science Association Conference Chairs

RECIPROCAL MEAT CONFERENCE 1948-1951 .W. H. Tomhave, The Pennsylvania State University 1952 ............................R. W. Bray, University of Wisconsin 1953 ............................. J. W. Cole, University of Tennessee 1954 .................... L. E. Walters, Oklahoma State University 1955 .................................E. A. Kline, Iowa State University 1956 ....................A. M. Pearson, Michigan State University 1957 ............. T. N. Blumer, North Carolina State University 1958 ........................V. R. Cahill, The Ohio State University 1959 ...........................C. H. Adams, University of Nebraska 1960 ...........................G. H. Wellington, Cornell University 1961 ....................... L. E. Kunkle, The Ohio State University 1962 ............... J. C. Pierce, U. S. Department of Agriculture 1963 ..............................J. D. Kemp, University of Kentucky 1964 .......................... E. J. Briskey, University of Wisconsin 1965 ....................................E. A. Pierce, Cornell University 1966 ...................... L. J. Bratzler, Michigan State University 1967 ....................... Z. L. Carpenter, Texas A&M University 1968 ............................. R. B. Sleeth, Armour and Company 1969 ................................... M. D. Judge, Purdue University 1970 ...............................A. M. Mullins, University of Idaho 1971 .......................... H. B. Hedrick, University of Missouri 1972 ............................ C. E. Allen, University of Minnesota 1973 ...............J. D. Sink, The Pennsylvania State University 1974 ....................James A. Christian, University of Georgia 1975 .............................G. C. Smith, Texas A&M University 1976 ......................... W. C. Stringer, University of Missouri 1977 ...................D. M. Kinsman, University of Connecticut 1978 ........................V. R. Cahill, The Ohio State University 1979 .......................M. E. Dikeman, Kansas State University 1980 ...................................E. D. Aberle, Purdue University 1981 ............................D. H. Kropf, Kansas State University 1982 .................... G. R. Schmidt, Colorado State University 1983 ................................... T. R. Carr, University of Illinois 1984 .............................L. J. Ernst, American Can Company 1985 .....................R. G. Kauffman, University of Wisconsin 1986 ................................... J. C. Forrest, Purdue University 1987 ......................... J. A. Carpenter, University of Georgia 1988 ..........................C. L. Kastner, Kansas State University 1989 ................ D. B. Anderson, Lilly Research Laboratories 1990 .......................... W. R. Usborne, University of Guelph 1991 ............................ M. C. Hunt, Kansas State University 1992 .............................J. T. Keeton, Texas A&M University 1993 .......................... C. R. Calkins, University of Nebraska 1994 .................................. R. E. Rust, Iowa State University 1995 ...... W. R. Henning, The Pennsylvania State University 1996 ....................................D. M. Allen, Excel Corporation 1997 .......... L. W. Hand, Protein Technologies International

1998 ................... L. C. Faustman, University of Connecticut 1999 ..................... J. R. Claus, Virginia Polytechnic Institute and State University 2000 ................................ H. G. Dolezal, Excel Corporation 2001 ...........................D. E. Burson, University of Nebraska 2002 ............................................C. D. Bacon, Tyson Foods 2003 ............................... D. S. Hale, Texas A&M University

MEAT INDUSTRY RESEARCH CONFERENCE

1965 .....................A. M. Mullins, Louisiana State University 1966 .................... A. M. Pearson, Michigan State University 1967 ............................. R. B. Sleeth, Armour and Company 1968 ............. T. N. Blumer, North Carolina State University 1969 ................................P. A. Goeser, Swift and Company 1970 ............................. M. E. Bailey, University of Missouri 1971 ................ W. E. Kramlich, John Morrell and Company 1972 ................................G. E. Brissey, Swift and Company 1973 .......................R. A. Merkel, Michigan State University 1974 ..................L. L. Borchert, Oscar Mayer and Company 1975 ..............................R. A. Field, University of Wyoming 1976 ........................... H. F. Bernholdt, Swift and Company 1977 ......................R. F. Kelly, Virginia Polytechnic Institute 1978 .............B. C. Breidenstein, Wilson Foods Corporation 1979 .................................. R. E. Rust, Iowa State University 1980 ......................H. E. Wistreich, B. Heller and Company 1981 ..............................J. D. Sink, West Virginia University 1982 .....................................R. W. Jabaay, Farmland Foods 1983 .......................R. W. Mandigo, University of Nebraska 1984 .............. W. C. Schwartz, Peter Eckrich and Sons, Inc. 1985 ...................................J. C. Acton, Clemson University 1987 .......... F. D. Dryden, George A. Hormel and Company 1989 ................................... M. D. Judge, Purdue University 1991 ..................... C. A. Hollingsworth, Bil Mar Foods, Inc. 1992 ............................. R. K. Miller, Texas A&M University 1993 ................... N. B. Webb, Webb Technical Group, Inc. 1994 ...............N. G. Marriott, Virginia Polytechnic Institute and State University 1995 .........S. H. Richert, Protein Technologies International 1996 ............................. J. R. Escoubas, Viskase Corporation 1997 ................... L. C. Faustman, University of Connecticut 1998 ........................................R. E. Rust, Rust & Associates 1999....................................... S. J. Eilert, Excel Corporation 2000 ..................... A. M. Booren, Michigan State University 2001 ....................L. C. Hand, Dupont Protein Technologies 2002........................................ L. N. Quint, ConAgra Foods 2003................................ S. D. Shivas, The Solae Company

iv American Meat Science Association

Officers of the American Meat Science Association

PRESIDENT R. W. Bray, University of Wisconsin.............................1965 L. E. Kunkle, The Ohio State University ........................1966 J. W. Cole, University of Tennessee..............................1967 L. J. Bratzler, Michigan State University........................1968 Z. L. Carpenter, Texas A&M University ........................1969 G. H. Wellington, Cornell University ...........................1970 M. D. Judge, Purdue University ....................................1971 A. M. Mullins, University of Idaho................................1972 H. B. Hedrick, University of Missouri ...........................1973 R. B. Sleeth, Armour and Company ..............................1974 J. D. Sink, The Pennsylvania State University................1975 J. D. Kemp, University of Kentucky ..............................1976 G. C. Smith, Texas A&M University..............................1977 L. L. Borchert, Oscar Mayer and Company...................1978 D. M. Kinsman, University of Connecticut ...................1979 R. A. Field, University of Wyoming ..............................1980 R. G. Cassens, University of Wisconsin ........................1981 D. L. Huffman, Auburn University................................1982 M. E. Dikeman, Kansas State University .......................1983 H. R. Cross, Texas A&M University ..............................1984 E. D. Aberle, University of Nebraska ............................1985 D. H. Kropf, Kansas State University.............................1986 W. G. Moody, University of Kentucky..........................1987 R. G. Kauffman, University of Wisconsin......................1988 W. C. Schwartz, Swift-Eckrich, Inc. ..............................1989 J. C. Acton, Clemson University ...................................1990 F. C. Parrish, Jr., Iowa State University..........................1991 R. W. Mandigo, University of Nebraska .......................1992 T. R. Carr, University of Illinois ....................................1993 C. L. Kastner, Kansas State University ...........................1994 D. B. Anderson, Lilly Research Laboratories .................1995 M. C. Hung, Kansas State University ............................1996 C. R. Calkins, University of Nebraska ...........................1997 D. M. Allen, Excel Corporation ....................................1998 J. T. Keeton, Texas A&M University..............................1999 L. W. Hand, Protein Technologies International ...........2000 C. A. Hollingsworth, Better Built Foods ........................2001 J. W. Savell, Texas A&M University..............................2002 J. G. Sebranek, Iowa State University............................2003

PRESIDENT-ELECT L. E. Kunkle, The Ohio State University........................1965 J. W. Cole, University of Tennessee..............................1966 L. J. Bratzler, Michigan State University........................1967 Z. L. Carpenter, Texas A&M University ........................1968 G. H. Wellington, Cornell University ...........................1969 M. D. Judge, Purdue University....................................1970 A. M. Mullins, University of Idaho ...............................1971 H. B. Hedrick, University of Missouri ...........................1972 R. B. Sleeth, Armour and Company..............................1973 J. D. Sink, The Pennsylvania State University ...............1974 J. D. Kemp, University of Kentucky ..............................1975 G. C. Smith, Texas A&M University .............................1976 L. L. Borchert, Oscar Mayer and Company...................1977 D. M. Kinsman, University of Connecticut ...................1978 R. A. Field, University of Wyoming ..............................1979 R. G. Cassens, University of Wisconsin ........................1980 D. L. Huffman, Auburn University................................1981 M. E. Dikeman, Kansas State University .......................1982 H. R. Cross, U. S. Department of Agriculture................1983 E. D. Aberle, University of Nebraska ............................1984 D. H. Kropf, Kansas State University ............................1985 W. G. Moody, University of Kentucky..........................1986 R. G. Kauffman, University of Wisconsin .....................1987 W. C. Schwartz, Swift-Eckrich, Inc. ..............................1988 J. C. Acton, Clemson University ...................................1989 F. C. Parrish, Jr., Iowa State University .........................1990 R. W. Mandigo, University of Nebraska .......................1991 T. R. Carr, University of Illinois ....................................1992 C. L. Kastner, Kansas State University...........................1993 D. B. Anderson, Lilly Research Laboratories.................1994 M. C. Hung, Kansas State University ............................1995 C. R. Calkins, University of Nebraska...........................1996 D. M. Allen, Excel Corporation ....................................1997 J. T. Keeton, Texas A&M University..............................1998 L. W. Hand, Protein Technologies International ...........1999 C. A. Hollingsworth, Keystone Foods ...........................2000 J. W. Savell, Texas A&M University..............................2001 J. G. Sebranek, Iowa State University ...........................2002 C. D. Bacon, Tyson Foods............................................2003

SECRETARY-TREASURER

W. C. Sherman, National Live Stock and Meat Board....................................................................... 1965-1975 H. K. Johnson, National Live Stock and Meat Board/National Cattlemen’s Beef Association ............ 1975-1996 D. J. Meisinger, National Pork Producers Council/National Pork Board............................................ 1996-2002 C. A. Hollingsworth, Better Built Foods ............................................................................................ 2002-

55th Annual Reciprocal Meat Conference v

Proceedings of the 56th Reciprocal Meat Conference

Table of Contents

2002-2003 American Meat Science Association Board of Directors .............................................................................i 2003 Committees of the American Meat Science Association......................................................................................ii American Meat Science Association Conference Chairs .............................................................................................iv Officers of the American Meat Science Association.....................................................................................................v Proceedings of the 56th Reciprocal Meat Conference Table of Contents .....................................................................vi

GENERAL SESSION I Preparing Undergraduate and Graduate Students to Meet Meat Industry Career Challenges, G. Smith ........................1

GENERAL SESSION II The Role of Extension in Meeting Meat Industry Challenges, R. Rust ...........................................................................5

MEAT QUALITY Biological Basis for Pale, Soft and Exudative Pork, M. Doumit*, C. Allison, E. Helman, N. Berry and M. Ritter ...........9 Genetic Basis for Pale, Soft and Exudative Turkey Meat, G. Strasburg*, and W. Chiang ............................................17 Pork Quality: Current and Future Needs of Industry and Academia, E. Huff-Lonergan, J. Melody*, R. Klont, and A. Sosnicki .................................................................................................................................................................23

SENSORY EVALUATION Utilizing Consumer Data in Product Development, L. Papadopoulos ........................................................................31

FOOD SAFETY Current Issues Related to Meatborne Pathogenic Bacteria, J. Sofos*, P. Skandamis, J. Stopforth, and T. Bacon ..........33 Postharvest Pathogen Interventions for Meat and Poultry, F. Pohlman*, and K. McElyea ...........................................39

RECIPROCATION SESSIONS Livestock and Poultry Care and Welfare, J. Swanson .................................................................................................49 Pork Muscle Profiling, D. Buege*, J. Sebranek, M. Doumit, D. Marple, D. Ahn, E. Huff-Lonergan, S. Lonergan, C.

Fedler, K. Prusa, E. Helman, and D. Meisinger......................................................................................................51 Cow Muscle Profiling, C. Calkins*, D. Johnson, and B. Gwartney .............................................................................53 Beef Muscle Profiling Research, D. Johnson*, K. Johnson*, C. Calkins, and B. Gwartney ..........................................55 Soy Protein Ingredient Technology, L. Hand ..............................................................................................................57 Computer Assisted Meat Science Education, S. Jones, V. Singh, and B. Franklin ........................................................59 More Than Words, Tips on Professional Speaking, B. Morgan ...................................................................................63 So You Want to Go to Graduate School: What to Consider, S. Lonergan*, J. Leheska, and D. McKenna ...................65 The Facts About Beef Cattle Growth Enhancement Technology, J.Lauderdale ...........................................................67 The National Pork Quality Benchmarking Study, D. Meisinger ..................................................................................71 Enhancing Meat Color Stability, D. Kropf ..................................................................................................................73 Carcinogens Formed When Meat is Cooked, J. Felton*, C. Salmon, M. Knize............................................................77

MUSCLE BIOLOGY: CLONING AND GENETICS Use of Cloning and Transgenesis in Pigs, R. Prather*, and D. Gerrard .......................................................................83

American Meat Science Association vi

INGREDIENT TECHNOLOGY Microbial Problems, Causes, and Solutions in Meat and Poultry Processing Operations, H. Brown .......................... 89 Natural Antioxidants Review, J. Haworth.................................................................................................................. 95

TEACHING Teaching Strategies for Preparing Students for the Meat Industry, M. Miller .............................................................. 99 Teaching Strategies for Preparing Students for the Meat Industry, T. Carr ................................................................ 103

POSTER ABSTRACTS Muscle & Lipid Biology........................................................................................................................................... 105 Pre-harvest Effects on Meat Quality......................................................................................................................... 109 Post-harvest Effects on Meat Quality ....................................................................................................................... 115 Processed Meat & Ingredient Technology ............................................................................................................... 127 Food Safety ............................................................................................................................................................. 133 Education................................................................................................................................................................ 137

55th Annual Reciprocal Meat Conference vii

American Meat Science Association 8

O P E N I N G G E N E R A L S E S S I O N

Preparing Undergraduate and Graduate Students to Meet Meat Industry Career Challenges

Gary C. Smith

Prelude Suppose You Wanted To Start A New University In 1963, serving as Faculty Advisor to the Washington

State University, College of Agriculture Student Council, I accompanied our student representatives to Winnipeg, Manitoba, Canada, to attend an “International Conference On Teaching In Agriculture.” The keynote speaker (J.R. Weir, Dean, Faculty of Agricultural & Food Sciences, Uni-versity of Manitoba) said: (a) “If you wanted to start a col-lege” (now, a university), “and had limited funds, for what would you initially spend money? First, you would build a classroom—so students could have a place to meet, to dis-cuss things, and to learn to communicate.” (b) “If additional money then became available, you would buy a book—with that, students could pursue scholarship, learning to think critically and, through verbal debate, discussing (communicating) interpretations of what the facts in the book were, what the author ‘said’ vs. ‘meant,’ and how the thoughts presented there could be made relevant.” (c) “Third, and only if more funds were available, you would buy pencils and paper so the students could begin to syn-thesize their thinking, to mull over their logic and interpre-tations, to commit their thought processes to paper, and to communicate their ideas in written form.” (d) “If, and only if, even more funding became available would a teacher be hired—and then, only, in the absence of a student leader grown up through the ranks—for surely, the propensity to lead would have surfaced from among those present in candid and open discussion sessions. A teacher’s presence is functional, of course, to explain and interpret the book in the light and context of other books and of the professor’s experience of things in and around and pertaining to the facts and ideas in the book and, secondly, to harness dis-course so that not too much time is wasted on frivolous

debate.”

My take on what Dean J.R. Weir was saying suggests this: Is that not the essence of the teaching/learning process—“Put ‘em in a room, buy ‘em a book and get ‘em pencils and paper; what follows will astound you”—but it will come at a price and one we can ill afford—it takes too long and the targets are too obscure. And, so, in our wisdom, we seek more highly structured thinking and communication and we sacrifice the opportunity to allow the students to learn to lead.

It was from such thoughts, and from—by that time—28 years of university teaching experience, that I concluded (Smith, 1989) that “To meet employer expectations, to compete in the workplace and to be perceived as an ‘edu-cated’ person, the animal science graduate must be able:

(a) to think critically,

(b) to communicate effectively, and

(c) to lead.”

By 2001, and—by that time—40 years of experience as a teacher of meat, animal and food sciences at three land-grant universities, I expanded my list of skills expected of graduates (Smith, 2001) to include:

(a) thinking critically,

(b) comparing logically,

(c) deciding independently,

(d) solving problems rationally,

(e) communicating effectively, and

(f) leading decisively.

I used many of those same thoughts, ideas and concepts from the 1989 and 2001 papers to write the “Introduction” for the Meat Evaluation Handbook (American Meat Science Association, 2001); this paper extends further the scope and horizon of coverage, to describe skill-sets needed by M.S., M. Agr. and Ph.D. graduates to meet the challenges of suc-cessful employment and careers in occupations within, or closely aligned to, the meat industry.

Gary C. Smith Department of Animal Sciences Colorado State University 1171 Campus Delivery Fort Collins, CO 80523-1171 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 1-4) June 15-18, 2003, Columbia, Missouri www.meatscience.org

56th Annual Reciprocal Meat Conference 1

Preparing Undergraduate Students To Meet Meat Industry Career Challenges

1. Thinking Critically To “think” is to formulate in the mind, to reason about, to

reflect on, to judge, and/or to decide. In the context in-tended here, “critically” means characterized by careful and exact evaluation and judgment. Critical thinking is acquired in formal courses that emphasize application of previously ingrained facts/knowledge, use of logic in problem solving, and implementation of principles involved in systems analyses. Careful structuring of practical laboratory exer-cises allows students to “learn by doing,” and of science-oriented laboratory exercises allows students to apply criti-cal thinking to the solution of problems. Ability to think critically can also be achieved in formal courses and in ex-tracurricular activities that involve animal/product selection, evaluation, grading and/or judging because comparative reasoning and application of memory standards are inte-grally involved in the decision-making processes.

2. Comparing Logically To “compare” is to examine in order to note the similari-

ties in, or differences between/among, things. “Logically” is defined as showing clarity and consistency of use of the principles of reasoning. Comparative reasoning is used, in opposition to memorization/regurgitation, in formal courses that require the weighing of options and/or the considera-tion of both the pro vs. con aspects in solving problems. The curriculum should include coursework involving com-puter-assisted, decision-making principles, like—for exam-ple—computerized breeding/selection analyses like those incorporated in the “Cow Game.” The ability to make logi-cal comparisons can also be taught in meat judging exer-cises that involve the ranking of cuts or carcasses and the assignment of quality or yield grades to carcasses.

3. Deciding Independently To “decide” is to make up one’s mind, to make or reach

a decision, and/or to pronounce a judgment or verdict. “In-dependently” means free from the influence of another or others, autonomously, and/or by self-reliance. Success, in many aspects of life, depends in large part of independence of thought and action, and—of course—on thinking and acting appropriately. Ability to make up your mind and reach a decision based solely upon your own opinion is vitally important in making personal and business decisions and is taught in formal courses that involve independent research study or which emphasize use of logic and ration-ale for problem solving. Providing students access to audio-tutorial learning allows for unstructured and self-paced mas-tery of subject matter. Experience in independent decision making is accomplished in meat judging because each competitor—acting independently and using only his/her own opinion—makes judgments and decisions.

4. Solving Problems Rationally To “solve” is to find a solution, an answer, or an explana-

tion for a problem. “Rationally” means exercising the ability

to reason in a sound, sane and logical manner. Rational problem solving is taught in formal courses in the general curriculum involving mathematics, statistical inference, business administration and economics, as well as in formal courses in the agricultural sciences dealing with agricultural economics, animal nutrition, animal breeding and capstone animal production courses. Offering livestock marketing courses that require each student to manage a live-stock/grain portfolio by making strategic daily/weekly trans-actions in the futures/options markets provides real-world problem solving experience. Rational problem solving can also be taught in judging/evaluation courses because com-parative reasoning, mathematical logic, sound judgments, conformity to an ideal, rank/order principles, memory stan-dards and knowledge integration must be used.

5. Communicating Effectively To “communicate” is to have an interchange of thoughts

or ideas and to make known your thoughts or ideas. “Effec-tively” means having the intended or expected effect and/or serving the purpose. Communication skills are formally taught in speech, technical writing and seminar courses and are further developed through involvement of students in meat judging (written reasons), livestock or wool judging (oral reasons), academic quadrathlons and quiz-bowls (oral and written presentations), and student clubs (if speaking/ writing opportunities occur). In meat judging, exhibits (car-casses or cuts) are ranked according to relative merit, notes are taken describing differences between and among exhib-its and a “written argument” is made to justify the student judge’s ranking decision. Written reasons are assigned scores by an expert who emphasizes accuracy and preci-sion—first and fore most—and syntax, penmanship, punc-tuation and grammar—secondarily. Oral reasons are as-signed scores by an expert who emphasizes—most—accuracy and precision, and secondarily, grammar, poise, style and delivery. Having to write or present a set of rea-sons forces the competitor to make decisions and to justify thoughts and ideas in a manner that will have the intended effect—to prove to the expert reading or listening to the set of reasons that the differences and similarities were ob-served and that decisions (whether right or wrong) were made rationally and logically.

6. Leading Decisively To “lead” is to be first, to be ahead, to steer, to guide,

and/or to show the way by going in advance. “Decisively” means having the power to settle a dispute or doubt in a firm, conclusive, resolute and determined manner. Nothing is provided in the formal coursework setting to encourage students to develop skills in leadership. Among the extra-curricular circumstances in which undergraduates can learn to lead and exert leadership skills are student government, student clubs, and internal or external competitions (live-stock exhibition teams, quiz-bowl squads, academic quad-rathlons and judging teams). Gerber (2003) said she was “a convert to the importance of the leadership lessons embed-ded in team participation,” that “team participation pro-vides powerful and unique leadership training” and “par-


ticipation in team sports builds understanding of teamwork and loyalty”; she was discussing team sports from an athlet-ics viewpoint but the principles apply to intercollegiate judging teams. Unique to student clubs, as contrasted with contests or competitions, are opportunities for officers and committee chairs to learn leadership skills in managing fi-nancial and human assets, developing and implementing organizational plans, orchestrating events and activities, and forming and sharing the vision, mission and goals of the unit or organization. In 1989, I had been a department head for nearly 8 years, and—from that vantage—felt comfortable in concluding that “Administrators must insist that student clubs and intercollegiate competitions are available to serve as an integral part of the process of developing student leadership among baccalaureate-level students in Animal Science” (Smith, 1989).

Preparing Graduate Students To Meet Meat Indus-try Career Challenges

1. Thinking Critically To think critically means “to reason about, to judge and

to decide by using careful and exact evaluation and judg-ment.” Graduate students learn to think critically by: (a) Being allowed—even encouraged—to doubt, to criticize, to question—rather than accepting as fact or truth whatever they read or hear. (b) Writing and reporting scientifically (improves clarity of thought and correct application of logic). (c) Reviewing the literature (there are good and bad studies; appropriate and inappropriate measures; right and wrong conclusions). (d) Editing and evaluating manuscripts (critiquing the work of others). (e) Debating, discussing, defending thoughts/ideas/opinions with subordinates, peers and superiors plus learning the art of graceful retreat and tactical concession.

2. Comparing Logically To compare logically means “to note the similarities in,

and differences between or among, things while clearly and consistently using the principles of reasoning.” Graduate students learn to compare logically by: (a) Applying the scientific method (observation, formulation of hypotheses and experimental testing—with controls and treatments) to detect differences between and among things. (b) Using tests of hypotheses, statistical inference and probabilities. (c) Grading papers and exams; scoring lab participation of in-dividuals. (d) Auditing—because essentially all mistakes, in GMPs, HACCP plans and animal-welfare programs are logic-based errors. (e) Judging carcass/product shows, speeches, science fairs, posters, record books or position papers—learning to rate/rank without bias, prejudice or favoritism.

3. Deciding Independently To decide independently means “to make up your mind

and reach a decision or make a judgment based solely upon your own opinion.” Graduate students learn to decide in-dependently by: (a) Realizing they will no longer be “spoon fed” but must read, debate, question and—ultimately—

synthesize an opinion of truth. (b) Setting priorities, yet still meeting critical milestones and deadlines. (c) Managing time and resources in a multiple-tasking work world. (d) Determining that—with pressure applied—they can push the envelope, doing more than they thought could be done. (e) Making decisions, when acting alone but as a represen-tative, that reflect favorably on the group, section, depart-ment, college and university.

4. Solving Problems Rationally To solve problems rationally means “to find a solution

and answer for a problem by reasoning in a sound, sane and logical fashion.” Graduate students learn to solve prob-lems rationally by: (a) Assessing the problem and accessing the information, to formulate and implement a solution. (b) Assisting with extension activities that deal with meat indus-try problem-solving scenarios. (c) Evaluating tests, proce-dures and protocols for use in performing a research assay or scientific determination. (d) Developing human-capital networks for present and future assistance in solving prob-lems. (e) Understanding “tool and toolbox” methodologies as building blocks and practical ways/means to affect a so-lution.

5. Communicating Effectively To communicate effectively means “to make known your

thoughts and ideas in a manner that will serve the purpose and have the intended effect.” Graduate students learn to communicate effectively by: (a) Serving as a teaching assis-tant, extension assistant, or laboratory instructor for a meat science course. (b) Developing the skill of “speaking in dif-ferent gears” to assure comprehension, irrespective of the education level of the listener. (c) Writing abstracts, reports and papers for audiences comprised of members of the lay-public, the industrial complex and the scientific commu-nity. (d) Preparing and presenting speeches and posters at industry and scientific meetings. (e) Interacting with those in attendance at teaching, research, industry and extension meetings (using “key word” conversational skills).

6. Leading Decisively To lead decisively means “to steer, guide or show to

(and, to be first and/or ahead of others) by making decisions in a firm, conclusive and resolute manner.” Graduate stu-dents learn to lead decisively by: (a) Being assigned respon-sibility for entire research projects and serving as project-leader from planning to completion. (b) Coaching intercol-legiate judging, grading and evaluation teams. (c) Develop-ing team-building skills while working on “company pro-jects” in research and outreach endeavors. (d) Mentoring fellow graduate students on subject matter, lab techniques, manipulative skills, statistical analyses, etc. (e) Serving as a substitute lecturer, teaching assistant, extension assistant or laboratory instructor.


Conclusion Knowledge, Yes, But Other Things Too.

Albert Einstein said (Gallagher, 2003) “A person who de-votes all his strength to objective matters will develop into an extreme individualist who, at least in principle, has faith in nothing but his own judgment.” A.W. Griswold said, (Campbell, 1972) “What is a college education? A college education is not a quantitative body of memorized knowl-edge…salted away in a card file. It is a taste for knowledge, a taste for philosophy, if you will…a capacity to explore, to question, to perceive relationships between fields of knowl-edge and experience.”

References American Meat Science Association. 2001. Meat Evaluation: Introduction.

pp. 6-8. In: Meat Evaluation Handbook. Copyright © 2001; ISBN: 0-9704378-0-3. AMSA, Savoy, IL.

Campbell, John. 1972. In Touch With Students…A Philosophy For Teach-ers. page 63. Copyright © 1972; ISBN 0-9600470-1-8. Kelly Press, Inc. Columbia, MO.

Gallagher, R. 2003. So, you think you’re a scientist? The Scientist (April 21 Issue). page 18.

Gerber, Robin. 2003. Team sports create leaders. USA Today (February 26 Issue). page 13A.

Smith, G.C. 1989. Developing critical thinking, communication skills and leadership in animal science students. pp. 1-6. Presented in a Teaching Symposium at the Annual Meeting of the American Society of Animal Sciences (Lexington, KY). Mimeograph Report, Department of Animal Science, Texas A&M University, College Station, TX.

Smith, G.C. 2001. Preparing animal science graduates to think critically, compare logically, decide independently, solve problems rationally, communicate effectively and lead decisively. pp. 1-8. Presented at the AMSA Meat Coaches & Administrators Lunch, Reciprocal Meat Confer-ence of the American Meat Science Association (Indianapolis, IN). Mimeograph Report, Department of Animal Sciences, Colorado State University, Fort Collins, CO.


I N T E R N A T I O N A L A W A R D L E C T U R E

The Role of Extension in Meeting Meat Industry Challenges

Robert E. Rust

Early History The idea of extension programs for the meat industry is

relatively new. It is, however, rooted in the concepts of the entire Cooperative Extension program, which, in itself, is less than a century old. Actually, Iowa is celebrating 100 years of Extension this year. While extension programs for production agriculture were well established when I began my professional career in the early 1950’s, programs for agricultural-related industries were new and even greeted with some skepticism by the old line Extension administra-tors.

When I began my career as an extension specialist at Michigan State, it was to pioneer a new effort to provide educational programs for the food retailers. Food retailing, at that time was largely the province of independent entre-preneurs who felt, and rightly so, that their existence was threatened by the large retail chains. Technologies such as new merchandising techniques, better sanitation, improved customer service, prepackaging and self-service meats were developing rapidly. We saw the leading food chains begin-ning to hire technically trained personnel to support these programs. Lacking that technical expertise in house, the independents turned to their local Land Grant University for support. In providing that support it became evident that the intermediate marketing step, the packer/processor, could also benefit from technical support.

Challenges One of the major challenges facing us at that time was

the lack of applied research information that is critical to the support of any viable extension program. Remember that in the early 1950’s Meat Science, as a distinct disci-pline, was in its infancy. Most of the research was centered

on meat animal composition. Very little was being directed toward meat processing problems. This meant convincing some of our researchers to redirect their efforts or relying on a body of knowledge that was emerging from within the meat industry itself or from supplier industries. Organiza-tions like the American Meat Institute Foundation Research Laboratory in Chicago were a most valuable resource. In retrospect, this was one of the most powerful groups of meat researchers ever assembled and I feel it was a severe loss when it was disbanded. This is an area where many European countries were well ahead of us with their gov-ernment and industry supported meat research institutes.

Another obstacle was establishing credibility with our prospective audiences. While the credibility of production agriculture-related extension activities was firmly rooted, business and industry still viewed us with some degree of suspicion. We had to prove the value of what we had to offer. Remember that, in the mid 1950’s, meat extension activities were confined to home butchering, carcass evaluation and quantity barbecues! In fact, even the con-cept of a Meat Science extension program was rare. At RMC’s in the mid 1950’s, Roy Snyder at Texas A & M and I were the only full time Extension Meat Specialists. There were a few others who shared duties with other extension activities or with teaching and research.

Believe it or not, one of the hurdles to overcome was the reluctance of Extension administrations to charge for exten-sion activities. They were still married to the idea that Ex-tension's services had to be “free.” That philosophy has changed 180 degrees! I recall one of the criticisms leveled at our early one-week short courses was that “ we didn’t charge enough.” It didn’t take me long to remedy that prob-lem! It is my experience that people tend to value informa-tion in direct proportion to the cost of that information.

Industry Activities Industry was working hard to fill the information gap.

Perhaps one of the most notable programs was the one-week short course offered by the Films Packaging Division of the Union Carbide Corporation (now Viskase) under the able leadership of Warren Tauber. This proved to be an excellent program to emulate.

Robert E. Rust Iowa State University 118 East 16th Street Ames, IA 50010 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 5-8) June 15-18, 2003, Columbia, Missouri www.meatscience.org


The American Meat Institute offered a series of corre-spondence courses for industry. After revising the text for the course on Sausage and Processed Meats Manufacturing, I convinced them to use this text as the basis for a series of two and one-half day seminars to be presented at various venues throughout the country. These were a lecture format using a mix of speakers from industry and academia. These proved to be popular with the meat industry and usually played to capacity audiences. Eventually, Iowa State “inher-ited” these courses from AMI as they directed their activities elsewhere.

The one drawback to a lecture type program is the re-striction on audience participation. If the audience comes largely from production operations, these people are not used to sitting for prolonged periods taking notes. Some form of “hands on” activity is far more appealing.

Industry Cooperation Industry cooperation in our extension programs has

proven to be essential. Many of the activities that we in-cluded in our short courses could not have happened with-out the help of the supplier industry and the participation of experts from the supplier and the meat processing industry itself. The early development of Iowa State’s one-week short course (now in its 25th year) was helped tremendously by participation in planning and program development from people like Hans Schneider of Teepak and consultants like Erwin Waters and Bill Shannon. The danger in using per-sons from the supplier industry is one of commercialization of the program. Nothing can destroy the credibility of a program, as well as the credibility of the speaker and the company he/she represents, faster than overt commerciali-zation. This has come through loud and clear when partici-pants turned in their evaluations of the program. Needless to say, it did not take long to “uninvite” an industry speaker who used this as an opportunity to commercialize. Fortu-nately we have a number of industry representatives who are thoroughly professional and objective in their approach. I won’t mention them by name here for fear of omitting someone.

Perhaps one of the prime examples of industry coopera-tion was the relationship we established that aided in the development of a Spanish language version of our Sausage and Processed Meats Short Course. Early on we began to have a number of Latin American visitors to our regular summer short course. Some of these even went to the extent of bringing their own translator along. With this evident need for a course in Spanish, we made a try at organizing one. Attempting to market this course was a failure and we abandoned the idea. We just did not have the contacts in the Latin American market to secure the required minimum audience.

Then, along came the late Dr. Abraham Saloma of Pro-tein Technologies International, now Solae, who agreed to cooperate with us in conducting the course. The result was successful and this cooperation continues on a more or less

annual basis to this day. I should add here that Dr. Saloma was one of the chief proponents of the AMSA International Award. I remember talking to him about the award, never dreaming at the time that I would one day be the recipient.

Translation Working with technical programs in another language

presents its own set of challenges. There is always the prob-lem of finding translators who are familiar with the technol-ogy. Good translators in the Meat Science area are few and far between. There is an amusing story that goes with this. For several years we hosted a group from the Czech Repub-lic and Slovakia as part of a US-AID program. The best translator that we found turned out to be a vegetarian!

We can often find technically competent translators who can handle alternate translation but finding those that can handle simultaneous translation is another story. Simultane-ous translation is an art in itself. A word or two of caution when using translators: never trust one that does not keep a note pad handy. This is how important facts can be “lost in translation.” Also, it is always helpful if there is someone in the audience that knows both languages and can alert you if the translator goes off course. I have been in a situation where the translator, who was knowledgeable in the tech-nical area, began to editorialize.

If you have the equipment and the facilities, I would much rather work with simultaneous translation. It doubles the amount of material you can cover. The effectiveness of simultaneous translation is reduced however, when it in-volves a hands-on demonstration. It does take a good deal of coordination between presenter and translator. I like to spend some time with the translator going over the details of a presentation, particularly if a demonstration is involved.

Working in Foreign Countries Many of you have been called upon to present technical

programs in other countries. I have learned, as I’m sure that many of you have that this is not as easy a task as it may seem when you first receive the invitation. My first advice is the same as the oft repeated line in the opening song in Music Man, “You gotta know the territory.” If at all possible, I like to get some feel of the product and the market that I will be dealing with. Many times, common US technology, no matter how good, just doesn’t fit the situation. While the addition of fat in a sausage formulation might reduce the cost here, it could increase the cost in a tropical country where fat often costs more than lean. Our US technology isn’t always the best when applied in certain foreign situa-tions.

It is also imperative to get some indication of the level of the audiences that you will be working with. Just as here in the US you wouldn’t want to present the same technology to a small processor making 25-pound batches that you would to someone with a 6000 pound per hour continuous frankfurter line. One size does not fit all.


If I am asked to put on a technical seminar in a country that I am not completely familiar with, I like to have at least a day if not more to observe the products in the local mar-ket and also some typical processing operations. In fact, I try to follow the same plan when doing an in-house seminar for a US processor. I definitely want to see the operation toward which I will be directing my remarks.

Demonstrations As much as I like hands-on demonstrations as a teaching

tool and as much as I enjoy doing them, I try to stay away from them unless I am thoroughly familiar with the venue. I have been burned too many times when I was assured that the facilities were complete and fully operational only to find, on the day of the program, that half of the stuffer parts were missing or that nobody in the organization had the faintest idea how the equipment went together. This even happened in a well-known meat research institute! After too many of these fiascoes, I insist on having a day prior to a demonstration type program for a dress rehearsal.

This same philosophy also applies to visual aids. I recall one instance where a colleague of mine and I were assured that PowerPoint projection equipment would be available. It was available all right but in one program the projector wasn’t compatible with the computer, in the next the pro-jector would not function at all and in a third we were greeted with “We thought that you were bringing the pro-jector.” Fortunately, we had our overhead transparencies as a backup, something I won’t leave home without. Relying on one medium for presentation is always a risky business.

One of the things that I have tried to avoid is a meat cut-ting demonstration. Generally the cutting pattern used in another country really does not match ours although it seems to adequately satisfy the local market. In fact, in many cases, I have found that cutting systems in use in some other countries make more sense than some of ours. Too often the audience gets caught up in technique and, as a result, loses the message that you are trying to convey. I recall the days when representatives from the National Live-stock and Meat Board would cut up a beef or hog carcass while wearing a tuxedo and never even got their shirt cuffs dirty. It wowed the audience but did it really convey any critical technology?

Extension in Other Countries As I mentioned earlier, the Extension concept is largely a

US phenomenon. The idea of a “university for the people” was the basic concept of the Land Grant system and Exten-sion was a natural offshoot. Many other countries followed a different route, that of the Meat Research Institute which often was a government/industry partnership. Technical conferences organized by these institutes were more the rule than the format of an applied teaching activity. In ef-fect, they were more like the old Meat Industry Research Conference where the AMIF presented the results of their

research efforts. The proceedings of the AMIF Research Conferences are still good references, by the way.

Recently I had an opportunity to talk to Dr. Svein Aage Berg of the Institute for Food and Biotechnology in Gote-borg, Sweden. He informed me that he was beginning a series of short courses for industry based on the format that he had observed while on sabbatical at Iowa State. I have also seen similar programs gaining in popularity in other countries.

Conducting programs in other countries can often bring some interesting challenges. Among these is the cultural difference. When working in the Czech Republic, we felt that it was important to introduce the concept of HACCP. This was an easy concept for them to embrace up until we got to the development of HACCP teams. Did you ever try to teach the concept of participatory management to some-one who had grown up under 50 years of totalitarian rule?

For a long period of time meat research institutes in other countries have offered consulting activities, either on a sub-scription basis or on a charge per project basis. This format is gaining popularity in the US and, with tightening budgets, may well become the Extension paradigm for the future. In all probability, the days of extension assistance “for free” may well be over.

Safety v. Technology This is an interesting challenge that is facing us with the

ever-increasing demand for food safety and HACCP related programs. I have talked with many of my former colleagues and find that they are devoting the larger share of extension time and effort toward supporting their clientele’s needs in developing and maintaining a viable HACCP program. I would hope that we, meaning Extension, would not aban-don the area of processing technology. If we do, someone will fill that void, most likely the supplier industry. While many members of the supplier industry can do an excellent job, let’s face it. They do have a vested interest and it would be a shame if we deprived the processors of a truly independent source of information. I hope that we will continue to maintain good processing technology as one of our objectives.

e.

Selling a Program The idea that, “If you build it they will come,” may have

worked in the movie “Field of Dreams” but my experience is that it doesn’t work in extension programs. A former professor of mine that taught adult education, used to say that there is no “felt need’ for continuing education. The need or interest must be driven by some outside force such as economics, the need to comply with regulations, etc. It is important to be cognizant of these driving forces and to capitalize on them when promoting a program. A lot of good programs have died because they were not properly promoted to the potential audienc


Professionalism Given my age, experience, white hair and the fact that I

am more than 50 miles away from home, I consider this a license to philosophize. More and more we find ourselves caught between the scientific truths and a position that is “politically correct.” With our muckraking “friends” in the popular news media stirring the spark of a smoldering breach in meat safety into a full-scale conflagration, some-one has to stand for the scientific truth. I have been stuck in that position many times. It ranged from the trivial like should we base the ultimate superiority of a meat animal on performance and carcass value or the opinion of some guru

to the livestock industry with a large hat, a loud voice and a cane to a serious issue like the perceived danger of nitrite in our processed meats. In the latter case I was caught squarely between the Des Moines Register, a couple of powerful members of Congress and the truth. That was one time I was really thankful for tenure. In the final analysis if we, as professional Meat Scientists don’t stand up for scien-tific truths, who will?

Remember too, that if you are going to pioneer a new program or concept you are going to be viewed as a here-tic. More than a few heretics in history got barbecued for their efforts!


M E A T Q U A L I T Y

Biological Basis for Pale, Soft and Exudative Pork

Matthew E. Doumit*, Chuck P. Allison, Emily E. Helman, Nicholas L. Berry and Matthew J. Ritter

Introduction Pale, soft and exudative (PSE) pork was recognized a half

century ago by Ludvigsen (1953). The undesirable appear-ance and texture, limited functionality, and inferior process-ing yield of PSE pork continue to make it a critical quality and economic concern (Cannon et al., 1996; Cassens, 2000). Rapid postmortem muscle acidification combined with high muscle temperature, as well as low ultimate meat pH, have long been implicated as factors that induce PSE pork characteristics (Briskey, et al., 1966; Sellier and Monin, 1994). Numerous reports on the development of PSE pork have focused on major gene effects, including the halo-thane (stress) gene (Fujii et al., 1991; reviewed by Louis et al., 1993) and the Napole gene (RN-; reviewed by Sellier and Monin, 1994; Milan et al., 2000). Despite an abun-dance of research describing PSE pork characteristics, and a reduction in the frequency of major genes with known dele-terious effects on pork quality, Cassens (2000) concluded that little progress has been made in reducing the incidence of PSE pork. The current paper will provide an overview of several biological processes associated with development of PSE pork, and highlight recent improvements in our under-standing of these processes that may be useful for devising approaches to reduce the incidence of PSE pork.

Stress Response Associated with Development of PSE Pork

Animal stressors, such as physical exercise, handling, transportation, mixing of pigs, noise, and weather extremes accelerate antemortem muscle metabolism and have ad-verse effects on meat quality (Tarrant, 1989). The biology of the stress response in animals has been the subject of sev-eral recent reviews (Schaefer et al., 2001; von Borell, 2001;

Miller and O’Callaghan, 2002; Wurtman, 2002). Miller and O’Callaghan (2002) defined stress as any disruption of ho-meostasis. Following disruption of homeostasis, the hypo-thalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) are activated in an attempt to preserve homeostasis (Miller and O’Callaghan, 2002). Initiation of the stress response via the HPA axis involves synthesis and release of corticotropin releasing factor (CRF) from the paraventricular nucleus of the hypothalamus. CRF travels down the axons of these neurons to the external layer of the median eminence. Release of CRF into the portal blood controls processing of adrenocorticotropic hormone (ACTH) in anterior pituitary corticotrophs, as well as secretion of several other pituitary hormones. Figure 1 illustrates the multi-hormonal control of ACTH release. ACTH released into the circulation stimulates the adrenal cortex to produce glucocorticoids, mineralocorticoids and adrenal androgens. One consequence of glucocorticoid release (primarily corti-sol in pigs) is an elevation in blood glucose, which provides the body with fuel necessary to meet the higher metabolic demands associated with a stressful situation. Local delivery of cortisol to the adrenal medulla induces the enzyme

Matthew E. Doumit Departments of Animal Science and Food Science & Human Nutrition 3385 Anthony Hall Michigan State University East Lansing, MI 48824 [email protected] The authors gratefully acknowledge support from the National Pork Board and the Michigan Agricultural Experiment Station. Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 9-15) June 15-18, 2003, Columbia, Missouri www.meatscience.org

Figure 1. Multihormonal Control of the Stress Response. Hypotha-lamic stimulation results in the release of corticotropin-releasing fac-tor (CRF), vasopressin (V) and vasoactive intestinal peptide. Each of these factors induces the anterior pituitary to release adrenocortico-tropin (ACTH). ACTH stimulates the synthesis of glucocorticoids in the adrenal cortex. Glucocorticoids can have a stimulatory effect on the adrenal medulla and result in the synthesis of epinephrine. Glu-cocorticoids can also act directly on the anterior pituitary to inhibit ACTH mRNA formation or inhibit ACTH release. The secretion of epinephrine can have inhibitory effects on the hypothalamus. Addi-tionally, epinephrine and norepinephrine can stimulate the anterior pituitary to release ACTH. Somatostatin (SRIF) has been shown to block the ACTH releasing ability of the anterior pituitary. (adapted from Axelrod and Reisine, 1984)


phenylethanolamine-N-methyltransferase, which is rate-limiting in epinephrine synthesis from norepinephrine (re-viewed by Wurtman, 2002). In turn, epinephrine stimulates glycogenolysis and is more potent than norepinephrine in raising body temperature and increasing heart rate and car-diac output. Chronic increases in epinephrine may be ex-pected to reduce adrenomedullary norepinephrine secre-tion. However, this may be compensated for by the stress-induced increase in the quantity of norepinephrine released from sympathetic nerve terminals, which may actually in-crease plasma norepinephrine and subsequently increase peripheral resistance and raise blood pressure (Wurtman, 2002). Collectively, the release of these hormones serves to adapt the body to stressors ranging from mildly psychologi-cal to intensely physical by affecting cardiovascular, energy producing, and immune systems (Axelrod and Reisine, 1984). Antemortem activation of the HPA axis and the plethora of related catabolic biochemical events also in-crease heat production and the likelihood of producing PSE pork (Schaefer et al., 2001).

Stress Reduction through Feed Manipulation Schaefer et al. (2001) and Rosenvold and Andersen

(2003) recently reviewed the role of nutrition in reducing antemortem stress and meat quality aberrations. Nutritional manipulation has included attempts to manipulate stress hormone levels (Schaefer et al., 2001), as well as direct at-tempts to buffer the well-known decrease in pH associated with antemortem stress (Boles et al. 1994). With regard to the latter, feeding bicarbonate resulted in moderate im-provements in texture and pH, whereas feeding an acidotic solution increased the incidence of PSE pork (Boles et al., 1994).

Attempts to modify the synthesis of hormones involved in the stress response in pigs by nutritional manipulation have produced inconsistent results. Magnesium may affect an animal's response and resistance to stress by antagonizing the effects of calcium on calcium-release channel function (Zucchi and Ronca-Testoni, 1997) or by altering the release of stress hormones (Classen et al., 1987). Feeding magne-sium aspartate to pigs has been shown to improve pork quality and reduce the incidence of PSE carcasses in pigs subjected to inferior handling (D'Souza et al., 1998; Schae-fer et al., 1993). Conversely, Caine et al. (2000) reported that supplementary magnesium exacerbated the PSE condi-tion in pigs heterozygous for the halothane gene, leading these authors to conclude that the efficacy of magnesium aspartate hydrochloride was dependent on diet and geno-type. Hamilton et al. (2002) observed no consistent effects of short-term feeding of magnesium sulfate on pork color and drip loss.

Exposure to stress increases catecholamine synthesis and turnover, thereby increasing the demand for tyrosine, which is the amino acid precursor of dopamine, norepinephrine and epinephrine. If catecholamine synthesis is compro-mised, animals become less resistant to stress and may lose

the ability to respond appropriately to stimuli. Likewise, insufficient serotonin is associated with violent behavior, but supplementation with tryptophan, the substrate for sero-tonin synthesis, may produce sedation (Schaefer et al., 2001). Adeola et al. (1993) reported that stress-susceptible pigs had lower brain levels of serotonin, dopamine, norepi-nephrine and epinephrine than stress-tolerant pigs. Simi-larly, Weaver et al. (2000) observed that boars heterozygous for the stress gene had lower basal plasma ACTH and corti-sol concentrations compared to wild-type boars. However, the neuroendocrine response to stress did not differ be-tween boars of these genotypes, despite a higher incidence of PSE meat in heterozygous boars. Feeding excess dietary tryptophan and tyrosine to pigs appears to have little effect on the incidence of PSE pork (Adeola and Ball, 1992; Schaefer et al., 2001).

Genetic Basis for PSE Pork Porcine stress syndrome (PSS), also referred to as malig-

nant hyperthermia, is a genetic abnormality that compro-mises a pig's ability to cope with stressors. Malignant hyper-thermia is inherited in an autosomal recessive fashion with incomplete penetrance (Mickelson and Louis, 1996). Pigs with this condition produce PSE pork more frequently than stress-resistant genotypes due to a combination of low pH and high early postmortem temperature, which results in extensive protein denaturation (Briskey et al., 1966; Louis et al., 1993). Initial studies to identify pigs affected by PSS util-ized the anesthetic, halothane gas (Eikelenboom and Minkema, 1974; Webb and Jordan, 1978). For over a dec-ade, halothane screening of pigs was used to identify ani-mals that were susceptible to PSS. This test was effective at identifying homozygous positive pigs, but did not distin-guish between heterozygous and homozygous normal pigs (Webb and Jordan, 1978). Cheah and Cheah (1976) showed that halothane enhanced the rate of calcium release by two-fold in pigs that were sensitive to halothane compared to those that were not. Advances in the understanding of cal-cium release from the sarcoplasmic reticulum (SR) led to the discovery of a substitution of T for C at nucleotide 1843 (HAL-1843) of the SR calcium-release channel cDNA (Fujii et al., 1991). This substitution is responsible for an alteration in amino acid sequence from an arginine to cysteine at residue 615 in the calcium-release channel protein, also called the ryanodine receptor (RYR1; Fujii et al., 1991). The polymorphism results in hypersensitive gating of the cal-cium release channel, which results in elevated sarcoplas-mic calcium. Numerous functions of sarcoplasmic calcium ions have been reviewed by Berchtold et al. (2000). A few of the many critical functions of sarcoplasmic calcium ions are depicted in Figure 2. Calcium release from the SR stimu-lates muscle contraction, SR calcium ATPase (calcium pump) activity, mitochondrial ATP synthesis, glycolytic ATP production, heat production, as well as calpain-mediated proteolysis. Excessive SR calcium release through defective RYR1 is often associated with rapid antemortem and post-mortem ATP utilization; increase rate of anaerobic glycoly-


sis, and the accelerated accumulation of hydrogen ions and heat associated with the development of PSE pork.

Based on the findings of Fujii et al. (1991), a DNA based test was established that could distinguish between homo-zygous positive, heterozygous carrier, and homozygous normal pigs with respect to the HAL-1843 mutation. This genetic test largely replaced halothane gas testing of swine, and efforts were made to eliminate the HAL-1843 mutation from commercial populations. Nonetheless, Murray and Johnson (1998) reported that in a population of 1006 pigs harvested in two packing plants, 90% of the PSE condition was caused by factors other than the HAL-1843 gene. Addi-tionally, Rempel et al. (1993) compared the DNA-based test with the halothane challenge test and found that several pigs classified as HAL-1843 free were responsive to halo-thane. One explanation for these results is that other RYR1 polymorphisms may exist and result in altered halothane sensitivity and calcium regulation. Indeed, more than twenty mutations in the human RYR1 have been linked to MH (Girard et al., 2001). Strasburg and Chiang (2003) pro-vide a more complete overview of RYR function and ab-normalities in these proceedings.

The Napole gene is another genetic abnormality that can lead to inferior pork quality. LeRoy et al. (1990) described the Napole gene as a dominant allele (RN-) and recessive allele (rn+) that is simply inherited. The dominant RN- allele results in higher than normal muscle glycogen stores and an extended postmortem pH decline that leads to pork with a lower than normal ultimate meat pH, higher reflectance (lighter meat), reduced water-holding capacity, and dra-matically reduced processing yield (LeRoy et al., 2000). Monin and Sellier (1985) referred to this condition as the Hampshire effect, due to its prevalence in the Hampshire breed. The causative polymorphism was identified in the PRKAG3 gene, which encodes a muscle specific isoform of the regulatory γ subunit of adenosine monophosphate-

activated protein kinase (AMPK; Milan et al., 2000). Acti-vated AMPK turns on ATP-producing pathways, inhibits ATP-consuming pathways, and can inactivate glycogen synthase (Hardie et al., 1998). The RN- allele results from an R200Q substitution in AMPK. This modification has little effect on early postmortem pH values, but the inferior color and water-holding capacity of RN- pork are associated with lower 24-hour pH values. The reduced water-holding ca-pacity of pork with low ultimate pH has been attributed to a reduced net protein charge that decreases repulsion be-tween myofilaments (Hamm, 1994), as well as a more pro-nounced denaturation of myosin tails and sarcoplasmic proteins (Deng et al., 2002). Conversely, Ciobanu et al. (2001) reported the presence of important alleles of the gene encoding AMPK that are associated with low glycogen content and improved pork quality. These findings demon-strate that additional alleles of genes involved in major mutations may be important contributors to pork quality.

Physical and Biochemical Aspects of PSE Pork Water-holding capacity of pork is influenced by protein

denaturation, myofibrillar lattice spacing, cytoskeletal links, membrane permeability, and the size of fluid channels in the extracellular space (reviewed by Purslow et al., 2001; Warner et al., 2001; Honikel, 2002). Recent nuclear mag-netic resonance measurements on pork longissimus muscle indicated that drip loss is an ongoing process involving the transfer of water from myofibrils to the extracellular space, and this process is affected by structural features at several levels of organization within muscle tissue (Bertram et al., 2002). The physical features of muscle that affect, or result from, fluid loss also influence pork color. Increased ex-tracellular fluid results in a pale product due to greater light reflectance and scatter. Pale color may also be associated with low myoglobin concentration or stability (reviewed by Faustman and Cassens, 1990). Zhu and Brewer (1998) found PSE pork to have lower metmyoglobin reductase and a higher proportion of metmyoglobin at the longissimus muscle surface than normal pork.

Many of the structural features of meat or meat proteins that affect color and water-holding capacity are dictated by early postmortem events. Schäfer et al. (2002) reported that early postmortem temperature and pH were sufficient to account for 89% of the variation in drip loss from pork. Klont and Lambooy (1995) also demonstrated the effects of temperature on water-holding capacity by experimentally inducing rectal and muscle temperature differences be-tween 36.9 and 39.6°C in anesthetized pigs. While these may be considered within the normal range of body tem-perature for pigs, an increase to the upper level of this nor-mal range caused an increased incidence of PSE meat in all halothane genotypes (Klont and Lambooy, 1995). It is also interesting to note that functional tests of mitochondria from normal and HAL-1843 heterozygous or homozygous pigs revealed that homozygous HAL-1843 pigs had more than twice the exo-NADH oxidase activity compared to normal pigs, whereas heterozygous MH pigs were intermediate

Figure 2. Calcium ions regulate skeletal muscle function. Calcium ions stimulate muscle contraction, sarcoplasmic reticulum (SR) cal-cium ATPase, glycogenolysis and glycolysis. Collectively, these proc-esses result in accumulation of lactate, hydrogen ions, and heat. A rapid accumulation of hydrogen ions and heat in postmortem muscle is associated with excessive protein denaturation and development of PSE pork. Pigs with the HAL-1843 polymorphism exhibit hypersensi-tive calcium release channels, and therefore a compromised ability to regulate sarcoplasmic calcium ion concentrations.


(Rasmussen et al., 1996). These authors speculated that exo-NADH oxidase activity might help sustain accelerated gly-colysis by re-oxidizing the cytosolic NADH as an alterna-tive to NADH shuttle activity. This process would be ex-pected to result in production of heat, but not ATP. Whether or not differences in exo-NADH oxidase contribute to varia-tion in heat production and pork quality in muscle of nor-mal pigs is currently unknown.

Poulanne et al. (2002) indicated that heat production ac-counts for 69% of the energy produced during the splitting of ATP to yield ADP and Pi. Thus, the activity of the myosin and/or calcium ATPases (Figure 2) during the antemortem and early postmortem periods are likely to play an impor-tant role in determining pork quality due to the heat pro-duction and glycolytic stimulation associated with ATP utilization. Although myosin ATPase activity is associated with specific myosin heavy chain (MyHC) isoforms, the relationships between MyHC isoforms and pork loin drip loss or color are generally low (Eggert et al., 2002; Huff-Lonergan et al., 2002; Ritter, 2002). Our attempts to explain harvest day effects on pork loin fluid loss revealed that a lower proportion of type IIA MyHC and a higher proportion of type IIB and/or IIX MyHC appear to contribute to accel-erated pH decline and increased fluid loss when less favor-able antemortem or early postmortem conditions are en-countered (Ritter, 2002).

Relatively low pH combined with high muscle tempera-ture during the early postmortem period causes denatura-tion and reduced solubility of sarcoplasmic proteins (Sayre and Briskey, 1963; Scopes, 1964; Joo et al., 1999) and my-osin (Offer, 1991; Warner et al., 1997). Pale color and re-duced water-holding capacity associated with PSE pork have been primarily attributed to denaturation of sar-coplasmic and myofibrillar proteins, respectively (Joo et al., 1999). However, Wilson and van Laack (1999) demon-strated that when myofibrils from either PSE or normal pork were combined with sarcoplasmic extract from PSE meat, the water-holding capacity of the myofibrils was lower than when combined with extract from normal pork. These au-thors concluded that sarcoplasmic proteins also influence water-holding capacity, through as yet undefined mecha-nisms. One possibility is that denatured sarcoplasmic pro-teins adsorb onto the surface of myofibrils, thereby shield-ing the charged groups available for fluid binding (Bendall and Wismer-Pedersen, 1962; Boles et al., 1992). Additional research is required to elucidate the mechanisms whereby sarcoplasmic proteins may influence water-holding capacity of meat.

Since the rate and extent of hydrogen ion accumulation have profound effects on pork quality, and hydrogen ion accumulation results from anaerobic glycolysis, regulation of glycogenolysis and glycolysis are important aspects of pork quality development. Muscle glycogen stores at the time of slaughter have long been recognized to influence meat quality (Briskey et al., 1966).

Proglycogen and macroglycogen can be distinguished on the basis of size and protein content, and have been de-scribed in detail by Lomako et al. (1993). In pigs, proglyco-gen is degraded preferentially during the first 45-60 minutes postmortem (Rozenvold et al., 2003). Furthermore, total glycogen and the proportion of acid-insoluble proglycogen are higher in muscles that exhibit rapid postmortem pH decline and PSE pork (Briskey and Wismer-Pedersen, 1961). Although the macroglycogen pool can be reduced by die-tary manipulation, a subsequent reduction in postmortem glycolysis is due to reduced metabolism of the proglycogen pool (Rosenvold et al., 2003). In a recent review, Rosenvold and Andersen (2003), citing unpublished observations of B. Essen-Gustavsson, suggested that early postmortem glycoly-sis in RN- pigs may be similar to that of non-carriers of the RN- mutation because the increase in glycogen in RN- pigs is due to greater macroglycogen stores. Consequently, total glycogen appears to be inversely associated with ultimate meat pH, whereas the rate of pH decline appears to be positively associated with the proportion of proglycogen.

In living skeletal muscle, energy utilization and energy production are highly coordinated events. In fact, Conley et al. (1997) suggested that elevated sarcoplasmic calcium activates muscle contraction, glycogenolysis and glycolysis in parallel (Figure 2), since glycolytic rate is dependent on muscle stimulation frequency and independent of ADP, AMP and Pi concentrations. Once again, this highlights the importance of calcium regulation on muscle metabolism. Control over glycolytic flux, or the flow of intermediates through glycolysis, may also be controlled by covalent modification (enzyme phosphorylation and dephosphoryla-tion), substrate control, and allosteric control mediated by changes in metabolite and co-factor concentrations (re-viewed by Connett and Sahlin, 1996). The reversible bind-ing of enzyme-enzyme and enzyme-contractile protein in-teractions provide additional possibilities for the regulation of glycolytic flux in skeletal muscle. The proportions of sev-eral glycolytic enzymes bound to contractile proteins in-crease with increased rates of glycolysis, and this may pro-vide a mechanism for enhancing metabolite transfer rates (Parkhouse, 1992). Lee et al. (1989) summarized several studies demonstrating that phosphofructokinase (PFK) is phosphorylated in contracting muscle when the need for energy is high. Modification of PFK by phosphorylation fa-vors enzyme binding to actin by increasing its apparent affinity for F-actin. It is currently not clear if enzyme modifi-cations that occur under normal physiological conditions will also occur under postmortem conditions, or if enzyme binding has adverse consequences relevant to pork water-holding capacity and color.

In a classical study of postmortem glycolysis, Kasten-schmidt et al. (1968) quantified levels of glycolytic interme-diates and co-factors in longissimus muscles that exhibited fast and slow rates of postmortem glycolysis. These authors concluded that accelerated glycolytic rates resulted from coordinated stimulation of glycogen phosphorylase, PFK, and pyruvate kinase (PK). These enzymes have traditionally


been considered to catalyze rate-determining steps of gly-cogenolysis and glycolysis in skeletal muscle, since the re-actions are far from equilibrium and reactions catalyzed by PFK and PK also proceed with a large decrease in free en-ergy.

Phosphofructokinase has been regarded as the primary regulatory enzyme of glycolysis. It was on this premise that Sayre et al. (1963) investigated PFK activity in porcine mus-cle extracts. These authors determined that in vitro PFK and phosphorylase activities were not associated with the rate of pH decline in longissimus muscle of Hampshire, Poland China and Chester White pigs. Surprisingly, Allison et al. (2003) found that maximal in vitro PFK activity extracted from longissimus samples obtained at 20 minutes postmor-tem was inversely correlated with loin chop fluid loss. This observation may reflect early postmortem inactivation of the acid labile PFK enzyme in muscle undergoing rapid glyco-lysis.

Schwägele et al. (1996) demonstrated that muscle from halothane-sensitive pigs had four times more total PK activ-ity than control pigs. Additionally, PK isolated from muscle of halothane-sensitive pigs lost only 30% of its activity when assayed at pH 5.5 rather than pH 7.0. In contrast, PK from control pig muscle lost >90% of its activity when as-sayed at pH 5.5. The higher activity and pH stability of PK from muscle of halothane-sensitive pigs were attributed to the presence of a more highly phosphorylated enzyme (Schwägele et al., 1996). These enzyme properties may al-low continued rapid accumulation of lactate and hydrogen ions in PSE muscle under conditions that would result in slow glycolysis in muscle producing higher quality pork. We recently reported that differences in PK capacity do not explain variation in color and water-holding capacity of pork loin muscle from HAL-1843-negative pigs (Allison et al., 2003). Additionally, when we measured PK activity at pH 5.5, we observed a loss of >88% activity in all loin muscle samples at this pH compared to activity measured at pH 7.0. Thus, factors that contribute to the PSE condition of pork from halothane-sensitive pigs may not be broadly ap-plicable to pigs that do not possess the HAL-1843 polymor-phism.

Xu et al. (1995) suggested that ATP may be functionally compartmentalized in both skeletal and cardiac muscle cells. These authors demonstrated that the entire chain of glycolytic enzymes from aldolase onward are bound to SR membranes from cardiac and skeletal muscle. Additionally, immunogold labeling of ultrathin sections revealed that pyruvate kinase was located on SR vesicles immediately adjacent to the calcium ATPase (Xu and Becker, 1998). Al-dolase and glyceraldehyde phosphate dehydrogenase were also found in close proximity to the calcium ATPase (Xu and Becker, 1998). ATP produced via SR associated glyco-lytic enzymes was shown to be preferentially used to fuel the calcium ATPase ion pump, suggesting that this ATP is transferred to the calcium pump in a protected microenvi-ronment and is functionally coupled to calcium transport (Xu et al., 1995). How (or if) the functional coupling of gly-

colytic enzymes to the major sites of energy utilization (my-osin ATPase and calcium ATPase) affects pork quality is currently unknown. However, this coupling may influence glycolytic rate, ultimate enzyme location and the degree of denaturation of sarcoplasmic proteins, which, in turn, may influence the color (Joo et al., 1999) and water-holding ca-pacity of pork (Wilson and van Laack, 1999).

Postmortem muscle glycolysis is frequently monitored by measuring pH at specified times. This measurement un-doubtedly reflects the pH of tissue, as opposed to that of individual muscle fibers, and may not accurately reflect the nature of postmortem glycolysis in individual muscle fibers. Oscillatory behavior of the glycolytic pathway has been well documented (reviewed by Smolen, 1995; Tornheim, 1979). In cell-free extracts of skeletal muscle, glycolytic oscillations are generated by repeated bursts of PFK activity. When the [ATP]/[ADP] ratio decreases to a trigger level, this initiates a sudden increase, or burst, in glycolytic flux that restores a high [ATP]/[ADP] ratio. In postmortem tissue, glycolytic bursts may also result in rapid and localized acidification, which could exacerbate protein denaturation. Using a protocol adapted from Tornheim et al. (1991), we have observed oscillatory behavior of glycolysis in sarcoplasmic protein extracts from porcine longissimus muscle (unpublished observations). The potential contribution of these oscillations to the development of PSE pork warrants further investigation.

Conclusions The complexity of the PSE pork problem is highlighted by

the fact that removal of genetic polymorphisms known to be associated with a higher incidence of PSE pork has not re-duced the incidence of the problem. Providing biological explanations for conditions that result in production of PSE pork is essential for development of new strategies to im-prove the quality and consistency of pork. Calcium ions play a key role in regulating skeletal muscle metabolism and function, and much remains to be resolved regarding the regulation of calcium signaling. Additional information is also required to identify factors that contribute to rapid postmortem glycolysis. A detailed understanding of factors that regulate postmortem glycolysis in porcine skeletal mus-cle will improve efforts to control the rate of muscle pH decline, and reduce the incidence of PSE pork.

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Genetic Basis for Pale, Soft and Exudative Turkey Meat

Gale M. Strasburg* & Wen Chiang

Introduction Consumer demand for poultry products over the last

three decades has led to unprecedented increases in poultry production, with turkey production alone increasing ap-proximately 180% since 1975 (National Turkey Federation, 2003). This increase was achieved, in part, by enhance-ments in growth rate and carcass yield, coupled with in-creases in breast proportion and reductions in abdominal fatness. The improvements on these traits are mainly due to the high heritabilities of body weight and body composition during breeding (Le Bihan-Duval et al., 1998). These achievements of breeding, however, have come with a hid-den cost in the form of increased frequency of meat quality problems (Sosnicki, 1993).

One of the most frequently recurring quality problems is that of pale, soft and exudative (PSE) meat. The term PSE is a descriptor for a meat product, typically pork or turkey, which has an abnormally light color, a flaccid consistency, poor water-holding capacity, and substantially reduced cook yield (Wismer-Pedersen 1959; Topel et al., 1976; DeSmet et al., 1996). Although the undesirable appearance of fresh meat cuts exhibiting the PSE condition may lead to rejection of the product by consumers, it is the poor protein functionality in processed meat products that is considered to be the primary cause of financial loss associated with PSE meat by the turkey processing industry.

The topic of meat quality problems, including PSE pork and turkey, was reviewed at this conference ten years ago by Louis et al. (1993) and Sosnicki (1993), respectively. Since then, numerous advances have been made in our understanding of the molecular mechanisms associated with excitation-contraction coupling in muscle, and of their potential relationship to meat quality. This paper provides

an update of the salient literature in this area, presents a hypothesis for a genetic component to development of PSE turkey, and describes some recent studies from our labora-tory that address this hypothesis.

Factors Influencing the Development of PSE Meat The mechanism by which PSE meat develops is still

poorly understood. It is generally accepted that PSE meat is closely associated with rapid, early-post-mortem glycolysis in muscle tissue (Ma and Addis, 1973; Pietrzak et al., 1997), which in turn results in accelerated rigor mortis develop-ment and low pH (<5.8) while the breast muscle tempera-ture is still high (Sosnicki and Wilson, 1992). The combina-tion of low pH and high temperature in the early stages of the conversion of muscle to meat leads to the denaturation of myofibrillar proteins and consequent loss of protein func-tionality.

Studies over the past decade have identified several ante-mortem environmental factors and post-mortem processing approaches that can enhance or mitigate meat quality (re-viewed by Sams, 1999). Stresses such as the onset of a pro-longed heat wave, transportation, and struggling of birds prior to slaughter have been shown to trigger the accelera-tion of postmortem glycolysis in turkeys producing PSE meat (McCurdy et al., 1996; McKee and Sams, 1997).

Genetic factors are likely to play a role in a bird’s relative stress susceptibility and its ability to adapt to stressors, thereby influencing the probability of developing PSE meat. Evidence for a genetic component of PSE turkey is limited, and is suggestive rather than direct. McCurdy et al. (1996) used color score measurements (L values) to assess the fre-quency of the PSE problem. Based on their observation that high L values were correlated with poor water-holding ca-pacity, they used a cut-off L value > 50 to classify turkey breasts as PSE. On this basis, they observed considerable flock-to-flock variation, with several flocks having as little as 1% and one flock as much as 29% of birds above this cut-off. Pietrzak et al. (1997) reported that turkeys could be classified as having fast or slow post-mortem glycolytic rates, and they suggested there was a genetic basis for these differences.

The striking similarity in development of the PSE condi-tion in turkey and pork, together with the identification of a

Gale M. Strasburg 334B G.M. Trout Bldg. Department of Food Science and Human Nutrition Michigan State Un iversity East Lansing, MI 48824 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 17-22) June 15-18, 2003, Columbia, Missouri www.meatscience.org


genetic component of stress susceptibility in pigs, suggest that there is a genetic basis for stress susceptibility in tur-keys. Therefore, it is instructive to briefly review the experi-ence of the pork industry with respect to the role of genetics in development of PSE meat.

During the 1950s and 1960s, genetic selection for lean, fast-growing pigs inadvertently led to increased frequency of severe stress susceptibility, known as porcine stress syn-drome (PSS), in various breeds of swine. Stresses such as transportation, heat, and mating in stress-susceptible pigs frequently led to episodes of malignant hyperthermia (MH), an inherited muscle disorder characterized by severe mus-cle contracture, excessive heat and lactic acid production (Mitchell and Heffron, 1982). An MH episode often results in death prior to slaughter, whereas live, stress-susceptible pigs that go through the slaughter process tend to yield a higher incidence of PSE meat than non-stress-susceptible pigs (Lundström et al. 1989).

By the 1980s it was recognized that an abnormal calcium release mechanism was a key factor in the development of PSS/MH, and by extension, the increased frequency of PSE meat from these pigs (Nelson, 1983; Cheah et al., 1984). The genetic basis of PSS/MH was subsequently identified as a point mutation in the skeletal muscle sarcoplasmic reticu-lum (SR) calcium-release channel (sometimes referred to as the ryanodine receptor or RYR1) (Fujii et al., 1991). The relationship of this mutation in RYR1 to muscle disease and meat quality will be explored below. Based on the apparent similarities of the basis for PSE pork and PSE turkey, we hy-pothesize that one or more mutations exist in turkey RYR which make a sub-population of turkeys stress-susceptible and thus, more likely than “normal birds” to develop PSE meat.

Ryanodine Receptors and Calcium-Release in Muscle Contraction

In all muscle cells, the cytosolic free calcium concentra-tion exerts primary control over the initiation, time course, and force of contraction. The process of coupling chemical and electrical signals at the cell surface to the intracellular release of Ca2+ and ultimate contraction of muscle fibers is termed excitation-contraction coupling (E-C coupling). The calcium release channel was initially identified in SR vesi-cles of rabbit skeletal muscle as a ryanodine binding protein (RYR1) because of its high affinity for ryanodine, a neutral plant alkaloid (Jenden and Fairhurst, 1969). This ligand-receptor interaction facilitated purification and characteri-zation of the SR calcium release channels (reviewed by Franzini-Armstrong and Protasi, 1997).

The ryanodine receptor is a homotetrameric channel pro-tein with subunit molecular mass of 565 kDa, consisting of about 5000 amino acids. RYR channel activity is modulated by numerous physiological and pharmacological factors (reviewed by Franzini-Armstrong and Protasi, 1997). Ago-nists of channel activity include µM Ca2+, mM caffeine, adenine nucleotides, halothane, and nM ryanodine,

whereas channel activity is inhibited by mM Ca2+, mM Mg2+, and µM ryanodine among many others.

Analysis of the RYR1 primary structure indicates that there are between four and ten membrane-spanning re-gions, and that about four-fifths of the molecular mass is localized on the cytoplasmic side of the SR membrane (Takeshima et al., 1989, Zorzato et al., 1990). The trans-membrane domains of each subunit monomer combine to form the pore of the channel that enables Ca2+ diffusion from the SR lumen to the sarcoplasm. The cytoplasmic do-main can be observed by electron microscopy as a square-like “foot” structure, which extends across the triad junc-tional gap between the SR terminal cisterna and the trans-verse tubule (t-tubule) membrane. The foot region of RYR also binds modulatory proteins including calmodulin (CaM) and FK-506 binding protein (FKBP). CaM binds to RYR1 with a stoichiometry of 4CaM/RYR1 (1 CaM per RYR1 sub-unit). CaM enhances channel activity at nM Ca2+ (corre-sponding to resting muscle Ca2+ concentrations), and it in-hibits channel activity at µM Ca2+ (corresponding to con-tracting muscle Ca2+ concentrations) (Reviewed by Hamil-ton et al., 2000). FKBP also binds with RYR1 with a stoichiometry of 4 FKBP/RYR1 and it appears to be impor-tant as a stabilizer of channel function (reviewed by Franzini-Armstrong and Protasi, 1997).

In skeletal muscle, ordered arrays of RYR molecules may couple with a protein complex known as the dihydropyri-dine receptor (DHPR) (Figure 1). DHPRs are clustered in the t-tubule as tetrads, and each unit of the tetrad can interact with a RYR1 molecule in the SR. However, a puzzling fea-

Figure 1. The E-C Coupling Complex in Mammalian Skeletal Muscle. The dihydropyridine receptor (DHPR) is a heterotetrameric protein embedded in the t-tubule that serves as the voltage sensor. The ryano-dine receptor (RYR1) is located in the SR. The cytoplasmic portion of RYR1 (also called the junctional “foot”) binds the modulatory proteins calmodulin (CaM) and FKBP (not shown). Upon depolarization of the t-tubule, the DHPR undergoes a conformational change, which is transmitted to RYR1, causing it to open. Calcium ions flow from the SR lumen through the transmembrane portion of RYR1 and into the cytoplasmic space. The structure of RYR1 is a low-resolution model derived from electron microscopy and image reconstruction. Greek letters represent DHPR subunits (From Hamilton et al., 2000 with permission).


ture of the structural disposition of DHPR tetrads relative to RYRs is that only half of RYR1 units are actually coupled to a DHPR, whereas alternate RYR1 foot proteins are not linked to DHPR proteins (reviewed by Franzini-Armstrong and Protasi, 1997). The mechanistic implications of this arrangement will be discussed below.

Skeletal muscle E-C coupling is initiated by action poten-tials, which are conducted along the sarcolemma and into the interior of the muscle fiber via the t-tubule. The stochas-tic-gating theory proposes that surface membrane depolarization alters the conformation of the DHPR, which triggers release of Ca2+ from the SR through RYR1 via a mechanical DHPR-RYR1 link, whereas the neighboring RYR1s, which are not physically coupled to the DHPR, are activated through a Ca2+-induced Ca2+-release mechanism (Franzini-Armstrong and Protasi, 1997). An alternative, co-ordinated-gating theory suggests that adjacent RYR1s are mechanically linked and that the linked RYR1s open and close in a coordinated fashion (Marx et al., 1998). Release of Ca2+ from the SR results in a rise in intracellular Ca2+ concentration, which activates the troponin complex, thereby initiating the contraction of the muscle.

Ryanodine Receptor Isoforms and Transcript Variants

The RYRs actually comprise a family of proteins, each with specific functions in different tissues. Messenger RNAs for three RYRs have been cloned and sequenced from mammalian tissues, and were identified as being encoded by separate genes (Mattel et al., 1994): ryr1 from skeletal muscle (Phillips et al., 1996), ryr2 from cardiac muscle (Na-kai et al., 1990), and ryr3 from brain and other non-muscle tissues (Hakamata et al., 1992). These genes share sequence identities in the overall range of 60-70% (Mattel et al., 1994). In contrast to RYR1, RYR2 and RYR3 are believed to operate solely by Ca2+-induced Ca2+-release (CICR).

Unlike mammalian muscle, two RYR isoforms termed α and β are present in nearly equal abundance in most avian, amphibian and piscine skeletal muscles (Airey et al., 1993b). On the basis of sequence comparisons with the mammalian isoforms, the amphibian and avian α and βRYRs are most similar in primary structure to the mammal-ian RYR1 and RYR3 isoforms, respectively (Ottini et al., 1996). The sequence similarity suggests that αRYR functions by “depolarization-induced Ca2+ release” (DICR), while βRYR operates through CICR. This hypothesis is supported by the observation that the Crooked Neck Dwarf mutant chicken, which lacks normal αRYR, fails to develop DICR on electrical or neuronal stimulation (Airey et al., 1993a). Also, the purified βRYR of bullfrog is about 20 times as sen-sitive to Ca2+ as αRYR in the Ca2+ dependent ryanodine-binding assay (Murayama and Ogawa, 1992). These and other observations led to a two-component model proposed by O’Brien et al. (1995) for the calcium release mechanism in non-mammalian vertebrate skeletal muscle (Figure 2). In

this model, the αRYR isoform is the RYR isoform directly coupled to DHPR, and the β isoform is the calcium-activated RYR isoform. Ca2+ released through the α isoform by DICR would bind to the cytoplasmic domain of the βRYR channel and trigger its opening by CICR. Recent evi-dence in support of this model has come from the work of Felder and Franzini-Armstrong (2002) who demonstrated that the β isoform in frog skeletal muscle SR is located at the periphery of the t-tubule/SR junction and thus does not make contact with DHPR.

Sarcoplasmic Reticulum

SarcolemmaDHPRα RYR

Ca2+

Ca2+

Ca2+ Pump

Ca2+

Ca2+

Ca2+

β RYRt-tubule

cytoplasm

Ca2+Ca2+

Ca2+

Ca2+

Sarcoplasmic Reticulum

SarcolemmaDHPRα RYR

Ca2+

Ca2+

Ca2+ Pump

Ca2+

Ca2+

Ca2+

β RYRt-tubule

cytoplasm

Ca2+Ca2+Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+Ca2+Ca2+

Ca2+

Ca2+

Figure 2. Schematic Diagram of E-C Coupling in Avian Skeletal Mus-cle. During E-C coupling, depolarization of the t-tubule triggers Ca2+-release via the αRYRs (blue), which are physically coupled to the voltage-sensing DHPR (red). The local increase in Ca2+ concentration results in Ca2+-induced-Ca2+-release from βRYRs (white), which are located at the periphery of the t-tubule/SR junction. Ca2+ is re-sequestered during relaxation by the Ca2+ pump (yellow).

Adding another layer of functional complexity, several variant mRNAs for RYR1, RYR2, and RYR3 have been iden-tified which are produced as a result of alternative splicing. Most of the splice variants are characterized by the pres-ence or absence of amino acid residues in either the modu-latory or transmembrane domain (Zorzato et al., 1994; Fu-tatsugi et al., 1995; Marziali et al., 1996; Miyatake et al., 1996; Tosso and Brenig, 1998; Jiang et al., 2003). For ex-ample, the deletions of Ala3481-Gln3485 and Val3865-Asn3870 in mouse RYR1 are near the regions postulated for phosphory-lation, and binding of Ca2+, calmodulin, and ATP. His4406-Lys4434 in rabbit RYR3 encompasses a predicted transmem-brane helix. The possibility that the alternative splicing of RYR proteins may have unique functional roles is supported by the findings that: 1) the RYR splice variant mRNAs are expressed in both a tissue- and a developmental stage-specific manner; 2) they are co-expressed in some tissues. A recent study showed that a RYR3 splice variant, which had a 29-amino-acid deletion of His4406-Lys4434, did not form a functional channel as expressed alone in HEK293 cells. However, when it was co-expressed with the wild type RYR3, it formed functional heteromeric channels with re-duced caffeine sensitivity (Jiang et al., 2003).

Ryanodine Receptor Mutations, Muscle Disease, and Pale Soft, and Exudative (PSE) Meat

Mutations in the mammalian RYR1 have been associated in humans with two muscle diseases: malignant hyperther-mia (MH) and central core disease (CCD). MH has been


recognized in humans since 1960 as an inherited skeletal muscle disorder characterized by accelerated muscle me-tabolism, glycogenolysis and glycolysis, severe muscle con-tracture, and rapidly rising temperature in response to ad-ministration of certain anesthetics such as halothane (Gron-ert, 1986; Ellis and Heffron, 1985). CCD is characterized by muscle weakness and the histological absence of oxidative or phosphorylase activity in central regions of muscle fibers (MacLennan, 2000). Moreover, CCD patients are generally considered to be at risk for development of MH upon ad-ministration of halothane.

To date, thirty missense mutations and one single amino acid deletion mutation in the primary structure of RYR1 have been described for MH. The mutations are clustered in three distinct regions of the RYR1 primary structure. The first region (mutation hot spot 1) ranges from amino acid residues 35 to 614 of the N-terminal domain, while the second region (mutation hot spot 2) ranges from residues 2162 to 2458 (Jurkat-Rott et al., 2000; Sambuughin et al., 2001). Both of these regions appear to form regulatory do-mains of the ryanodine receptor, which control sensitivity of the channel protein to regulatory ligands modulating Ca2+ release. The recent discovery of the Thr4826Ile mutation for MH (Brown et al., 2000), together with the identification of at least seven mutations for CCD in the region of amino acids 4550 – 4940 (reviewed by Jungbluth et al., 2003), suggests that the C-terminal region of RYR1 may represent a third mutation “hot spot.” The overall physiological effect of the MH/CCD mutations is elevation of resting muscle Ca2+ levels as a result of increased Ca2+ permeabilities of the mu-tant channels (MacLennan, 2000). The extent to which Ca2+ levels are raised depends on the nature of the mutation and on the ability of the muscle to elaborate compensatory mechanisms by increasing expression of the Ca2+ pump to maintain Ca2+ homeostasis.

One mutation, Arg614Cys, found in human MH is also as-sociated with porcine MH as an Arg615Cys mutation. This mutation of RYR1 causes the channel to be hypersensitive to stimulators of opening and does not close readily. Thus, as pigs carrying the homozygous mutated ryr1 gene en-counter stress before or during slaughter, their muscle cells would be flooded with excess Ca2+, leading to sustained muscle contraction and enhanced glycolytic and anaerobic metabolism. The resultant excess lactic acid and heat pro-duction would lead to the ultimate development of PSE meat.

Evidence for Genetic Differences in Turkey RYRs The potential for a genetic predisposition in turkeys to

yield PSE meat prompted us to conduct a series of experi-ments to determine if differences exist in turkey skeletal muscle RYR channels. Since the PSE-susceptible turkey is thought to be associated with modern, rapidly growing commercial turkeys, we proceeded with the hypothesis that genetic selection has resulted in increased frequency of altered RYRs in modern commercial turkeys. We compared

the frequency of PSE incidence between a random-bred, genetically unimproved line and a commercial line of tur-keys intensively selected for rapid growth and increased muscling. Birds were subjected to the same level of heat stress immediately before slaughter. Over 50% of the com-mercial turkeys were categorized as PSE, while only 25% of the random-bred birds had the PSE characteristics, thus supporting our hypothesis.

To determine whether altered ryanodine receptors were responsible for the differences in meat quality, we devel-oped a modified ryanodine-binding assay based on that of Mickelson et al. (1988). These workers had shown that RYR1 in SR from genetically defined stress-susceptible pigs had higher affinity (lower Kd value) for ryanodine than that of non-stress-susceptible pigs. The difference in affinity was ascribed to differences in primary structure of RYR1. We used the ryanodine binding assay to screen skeletal muscle SR preparations of the two turkey populations for the possi-ble altered RYR activity. Our ryanodine binding results (Wang et al., 1999) indicated that indeed there were differ-ences in affinity of ryanodine for the RYRs in these two populations, similar to that observed between the two lines of pigs. We identified a commercial turkey group with a significantly higher affinity for ryanodine compared to that from genetically unimproved turkeys. We found another commercial turkey group with approximately the same af-finity for ryanodine as the random-bred turkey group (Zhang, 2000; Table 1). These differences suggest that there is heterogeneity of the RYR channel activity between the random-bred and commercial turkey populations. Table 1. Dissociation constant (Kd) of RYR among different turkey groups obtained from [3H]ryanodine binding assay.

Turkey Groups Kd Random Bred (R, N=8) 16 ± 2 nMa

Commercial Group A (Ca, N=17) 8 ± 1 nMb

Commercial Group B (Cb, N=5 19 ± 2 nMa a,bsignificantly different (P<0.01)

Until recently, it was unclear whether this difference in ryanodine-binding activity represents differences in the αRYR or in the βRYR, or in both isoforms. A recent study of bullfrog RYR channel activity in SR vesicles by Murayama and Ogawa (2001) may prove informative. They demon-strated that in frog SR vesicles, which are structurally and functionally similar to turkey SR, the αRYR ryanodine bind-ing activity is almost completely suppressed. They further demonstrated that ryanodine binding in frog SR is the result of βRYR activity. If confirmed in turkey SR, our results would suggest that the differences RYR channel activities in our study could be ascribed to differences in amino acid sequence in the βRYR isoform.

In addition to the possible genetic difference identified in the turkey βRYR isoform, we also have identified differences in the αRYR isoform. At least three transcript variants differ-ing by the presence or absence of 81 bp or 193 bp have been found. The missing nucleotides would be located


within the region of mutation hot spot 1. Two different αRYR alleles were also identified in our laboratory. Com-parison of genomic DNA and cDNA sequences suggested that the absence of these nucleotides in the cDNA sequence results from alternative splicing. The splicing could occur in both alleles. The frequency of splicing and factors influenc-ing the expression of these transcript variants and their rela-tionship to meat quality are under investigation in our labo-ratory.

Ellis, F.R; Heffron, J.J.A. 1985. In Recent Advances in Anaesthesia and Analgesia (Atkison, R.S., and Adams, A.P., eds) No. 15, pp. 173-207, Churchill-Livingstone, London.

Felder, E.; Franzini-Armstrong, C.A. 2002. Type 3 ryanodine receptors of skeletal muscles are segregated in a parajunctional position. Proceed-ings of the National Academy of Science USA 99: 1695-1700.

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Conclusions The genetic basis for PSE turkey meat is still not clear, but

advances in our understanding of ryanodine receptor activ-ity and variation make it likely that one or more mutations in turkey skeletal muscle RYR predispose birds to the devel-opment of PSE. Mutations could exist in either the αRYR or αRYR isoform or in both isoforms. Here we have presented evidence of genetic differences in both isoforms, which might be related to the occurrence of PSE turkey. Future research will focus on the correlation of the genotypes of turkey with their phenotypes including meat quality traits. The ultimate goal of our research is to provide reliable ge-netic tests for breeding stock that will yield optimal quality turkey meat.

Futatsugi, A.; Kuwajima, G.; Mikoshiba, K. 1995. Tissue-specific and de-velopmentally regulated alternatice splicing in mouse skeletal ryano-dine receptor mRNA. Biochemical Journal 305: 373-378.

Gronert, G.A.; 1986. Malignant Hyperthermia. In Myology (Engel, A.G., and Banker, B.Q., eds) pp. 1763-1784, McGraw-Hill Publications, Minneapolis, MN.

Hakamata, Y.; Nakai, J.; Takeshima, H.; Imoto, K. 1992. Primary structure and distribution of a novel ryanodine receptor/calcium release channel from rabbit brain. FEBS Letters 312: 229-235.

Hamilton, S.L; Serysheva, I.; Strasburg, G.M. 2000. Calmodulin and excita-tion-contraction coupling. News in Physiological Sciences 15: 281-284.

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Jiang D.; Xiao, B.; Li X.; Chen, S.R.W. 2003. Smooth muscle tissues express a major dominant negative splice variant of the type 3 Ca2+ release channel (ryanodine receptor). Journal of Biological Chemistry 278, 4763-4769.

Acknowledgements The authors gratefully acknowledge the contributions of

Dr. Todd Byrem, Dr. Al Booren, Dr. John Linz, Dr. Li-Ju Wang, Dr. Kevin Roberson, Ms. Haiyan Zhang, Mr. Chuck Allison and Mr. Mike Maile to the work reported here. This work was supported by the USDA National Research Initia-tive, the Michigan Animal Industry Coalition, and the Michigan Agriculture Experiment Station.

Jungbluth, H.; Sewry, C.A.; Muntoni, F. 2003. What’s new in neuromuscu-lar disorders? The congenital myopathies. European Journal of Paedatric Neurology. 7:23-30.

Jurkat-Rott, K.; McCarthy, T.; Lehmann-Horn, F. 2000. Genetics and pathogenesis of malignant hyperthermia. Muscle & Nerve 23: 4-17.

Le Bihan-Duval, E.; Mignon-Grasteau, S.; Millet, N.; Beaumont, C. 1998. Genetic analysis of a selection experiment on increased body weight and breast muscle weight as well as on limited abdominal fat weight. British Poultry Science 39: 346-353.

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Pork Quality: Current and Future Needs of Industry and Academia

Elisabeth Huff-Lonergan, Jamie Melody*, Ronald Klont, and Andrzej Sosnicki

Introduction It is generally recognized by the meat (pork) industry and

academia that a “status quo” has been reached between production of pork quantity (carcass leanness) and quality (meat eating and processing attributes), and that the new directions for the industry are being clearly defined by con-sumer trends. As a consequence, the pork industry focuses on least cost practices to produce the desired “Quality Lean”. When looking at a bell-shaped curve for pork qual-ity, it is usually the bottom ‘tail’ that results in the greatest losses or otherwise, known as pale, soft, exudative (PSE) pork. The industry has made great strides in reducing the incidence of PSE over the past 30 to 40 years. The preva-lence of PSE in the US industry was 18% in 1963 (hams; Forrest et al., 1963) and 16% in 1992 (loins; Kauffman et al., 1992). In a more recent study, the incidence of PSE was 9.8% (loins; Scheller et al., 1996).

Although the incidence of PSE has dramatically de-creased in the last 30 years, the concerns about the varia-tion of meat quality continue. Implementation of statistical process control principles by the industry has dramatically helped to control and optimize the genetic and environ-mental factors, which influence meat quality. Rapid ad-vancement in life sciences; i.e., TGRM (Total Genetic Re-source Management), functional genomics, proteomics, and muscle biology, is also generating new quantitative genet-ics, molecular biology, physiological and biochemical tools for creation and sustainability of pork supply systems orien-tated towards meat quality (Rothschild and Plastow, 1999; Kinghorn et al., 2002; Knap et al., 2002).

The objective of this paper is to summarize the current status of academic knowledge of pork quality and its appli-cation by the industry. Conceivable directions for the aca-demic research and industry implementation are also pro-

vided.

Pork Industry Achievements The world meat industry, like many other agricultural

and non-agricultural industries, is constantly undergoing changes. The most prominent change of the last few years has been consolidation leading to bigger, and more com-plex, vertically integrated and/or coordinated meat industry entities. Also, in most parts of the world, the percentage of further processed meats is increasing at the expense of fresh meat consumption. End users, like meat/food processing companies, although tending to view meat as “just” raw material or more precisely as a protein source, are becom-ing more aware that “raw” meat proteins must have consis-tent and specific quality/functionality characteristics. Retail and food service businesses are also becoming more inter-ested in consistently-sized “case-ready” products, better tasting product varieties, and cuts of meat that are suited to today’s consumer cooking demands, including demands for ready-to-eat products. These consumer demands have also led to product differentiation and greater focus on the value of meat quality parameters, especially tenderness, juiciness and flavor of fresh and value-added pork products (Gresham et al., 1994; Hofmann, 1994; Madsen and Thod-berg, 1994).

It is commonly acknowledged that meat quality is a diffi-cult characteristic to assess as many different aspects, both objective and subjective, make up the overall trait (Hof-mann, 1994). Some systems/markets require specific quality characteristics such as high intramuscular fat content or dark color; i.e. dry cured ham production or the Japanese market. Several markets have started to demand different slaughter weights; e.g., in the UK to minimize boar taint of intact males, or to market portion-controlled size meat cuts in the US for “case-ready” products. A further increase in product diversification has stimulated growth of niche mar-kets with different requirements for raw materials and ready-to-cook and ready-to-eat, branded consumer prod-ucts.

As a response to the growing meat quality awareness of the consumer, the pork industry has successfully imple-mented several processes to improve meat quality, and still simultaneously has improved production performance and

A. A. Sosnicki 3033 Nashville Road Franklin, KY 42134 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 23-29) June 15-18, 2003, Columbia, Missouri www.meatscience.org


carcass quality. There are several relatively inexpensive meat quality measurements, such as initial and ultimate pH, that have been successfully included in some breeding pro-grams (Eikelenboom et al., 1995; Sosnicki et al., 1998), and by several industry entities.

Food safety issues have accelerated the introduction of different quality assurance control systems in the meat in-dustry, like Hazard Analysis of Critical Control Points (HACCP), General Manufacturing Practices (GMP), Total Quality Management (TQM), International Standards Or-ganization (ISO), or Six-Sigma (Wood et al. 1998; www.6-sigma.com). It is important to note that several food safety critical control points apply to meat quality control proc-esses (Hoen, 1996; Sosnicki et al., 1998).

At the same time there is a growing consumer concern about “the quality” of meat production. There is no doubt that the consumer is now at the center of a considerable turmoil involving the entire food supply chain. Food safety crises and livestock epizooties have shaken both consumers and political confidence in animal/food science, and the meat chain at large. Harrington’s (1994) list of consumer concerns: ethical, food safety, nutrition and fat, animal wel-fare, “third world”, the environment and genetic engineer-ing, remains as true today as it was a few years ago.

Directions for Basic & Applied Research Muscle Biology Research

Muscle differentiation. The control of muscle growth in-volves many genes and a complex array of transcription factors. Terminal myogenic differentiation is characterized by expression of four transcription factors that are members of the myogenic determination factor (MDF) family: myo-genin, MyoD, Myf5 and MRF4 (Mulvaney, 1994; Molkentin and Olson, 1996; Arnold and Winter, 1998; Arnold and Braun, 1996; Te Pas et al., 2000). Additional transcription factors, particularly the MEF2 family, cooperate with the MDFs to activate muscle-specific gene transcription (Black and Olson, 1998; Ridgeway et al., 2000). A third group of transcription factors, termed NFAT (Nuclear Factor of Acti-vated T cells) has also been found to affect the transcription of certain genes. At least five different NFAT isoforms have been identified (NFAT1-5), with NFAT2 and NFAT4 being present in larger amounts in skeletal muscle (Hoey et al., 1995).

Muscle growth/Muscle fiber types. Myogenesis is fol-lowed by fiber hypertrophy and maturation, including DNA addition through satellite cell proliferation and fusion, to yield adult muscle fibers (Swatland, 1973; Lengerken et al., 1994). The biochemical profile of adult muscle greatly in-fluences its metabolic responses during pre-slaughter han-dling and, subsequently, postmortem conversion of muscle to meat and meat quality. One of the main factors determin-ing muscle biochemical pathways is fiber type composition: skeletal muscle is composed of different types of fibers, which are the results of co-ordinated expression of distinct sets of structural proteins and metabolic enzymes (Pette and

Staron, 1990; Musaro et al., 1995; Schiaffino and Reggiani, 1996). Fiber types are often defined by the isoforms of my-osin heavy chain (MyHC) that are present. There are four major fiber types in postnatal pig muscle characterized by the expression of the slow/I/β, 2a, 2x and 2b MyHC gene isoforms. The slow/I/β and 2b fibers, also known as slow-oxidative and fast-glycolytic, respectively, represent two extreme metabolic profiles. The 2a and 2x fibers are inter-mediate fast oxidative-glycolytic fibers. (Chang and Fernan-des, 1997; Greaser et al., 2001). In addition, fiber type is affected by several environmental factors; for example diet or physical activity (Karlsson et al., 1993; Klont et al., 1998; Petersen et al., 1998; Karlsson et al., 1999).

Fiber type can also be affected by thyroid hormone status. T3 binds to specific receptor proteins in the nucleus (TR) that in turn bind to DNA thyroid response element re-gions (TRE) upstream of the promoter region of many mus-cle genes (for example - type I myosin heavy chain, the sar-coplasmic reticulum calcium-ATPase, and the GLUT4 glu-cose transporter). Four different TR isoforms are produced by alternative splicing; thus, changing expression of many genes and changing the fiber type proportions (Caiozzo et al., 1993).

The impact of muscle fiber type composition on lean quality is not well understood (Essen-Gustavsson and Fjek-jer-Modig; 1985; Degens and Veerkamp, 1994; Lefaucheur et al., 1995; Larzul et al., 1997; Tanabe et al., 1997). How-ever, a relative high volume of Type IIb fibers was related to poor meat quality by many authors (Brocks et al., 1998; Essen-Gustavsson and Fjekjer-Modig; 1985; Fiedler et al., 1999; Lefaucheur et al., 1995; Larzul et al., 1997; Sosnicki, 1987). Published heritabilities (h2) of muscle fiber traits are moderate to high; i.e. h2 of Type I fiber CSA = .59; h2 of Type I fiber percentage = .46; h2 of Type IIb fiber percent-age = .58 (Larzul et al, 1997). Published genetic correla-tions (rg) indicate that Type I and Type IIb fiber percentage are negatively related (rg = -.85; Larzul et al., 1997). This particular genetic correlation indicates that breeding for higher percentage of Type I fibers would decrease the pro-portion of Type IIb fibers; thus directionally improving meat quality without negatively affecting Type IIa and IIx per-centage (rg = .16) or mean fiber CSA (rg = -.15). This ap-proach would enable selection for fast lean tissue growth rate without negatively affecting meat quality (Larzul et al., 1997; Klont et al., 1998).

In summary, continuation of skeletal muscle biology re-search is needed to fully understand the mechanisms of muscle differentiation, growth and metabolism, thus to bet-ter understand how to efficiently produce high quality meat.

Stress Welfare Research The interaction between skeletal muscle and environ-

mental stress before slaughter complicates even further the understanding, measurement and control of the major sources of variation in meat quality. Stress experienced by the animal prior to harvest can have a profound impact on muscle metabolism in the first few hours after exsanguina-


tion. There is a major need for more information regarding specific physiological impacts of the stress response in early postmortem muscle. Understanding the basic mechanisms involved could ultimately lead to better carcass and/or ani-mal management schemes to reduce the variation in pork quality. For example, the magnitude of stress response de-pends on the individual characteristics of the animal; i.e., the individual difference in behavior and physiology may have consequences for the ability of the pig to cope with unfamiliar stimuli such as pre-slaughter stress (Benus et al., 1987; Tarrant, 1989; Lawrence et al., 1991; Hessing et al., 1994). The two main neuro endocrine systems involved in physiological adaptation and metabolic regulation are the hypothalamic-pituitary adrenal axis (HPA) and the auto-nomic nervous system (Harbuz and Lightman, 1992). The genetic differences in the basic functioning of these neuro endocrine systems or in their response to stress need to be fully explored and implemented in the breeding programs (Benus et al., 1991; Habuz et al., 1992; Mormède et al., 2002).

Quantitative and Molecular Genetic Research Meat quantity and quality are determined by a combina-

tion of genetic, nutritional and environmental factors and their interactions (for review see Cassens et al., 1975; Tar-rant, 1989; Cameron, 1990; Sosnicki et al., 1998). Genetic effects play a crucial role in “designing” pig carcass compo-sition and quality; although the heritability of pork quality is lower than of meat quantity; i.e., generally between 10% and 30% of the variation in meat quality traits such as ulti-mate pH, color, water holding capacity, drip loss, tender-ness, etc; is determined by the genetic make-up of the ani-mal (De Vries et al., 1994; Sosnicki et al., 1998). The use of quantitative genetics, selection indexes, estimated breeding values (EBVs), and total genetic resource management (TGRM) for carcass and meat quality has enabled the pork industry to make progress on these traits (Hanenberg and Merks, 2000; Hill, 1999; Woolliams et al., 1999). The EBVs of some of the breeding organizations now include meat quality traits in addition to efficient production of carcass lean (Sosnicki et al., 1998; Kinghorn et al., 2002; Knap et al., 2002).

Identification of genetic markers and candidate genes for meat quality characteristics in combination with Marker Assisted Selection (MAS) programs has started to greatly enhance genetic improvement for meat quality whilst not compromising lean percentage (Meuwissen and Goddard, 1996; Short et al., 1997; Rothschild and Plastow, 1999; Ciobanu et al., 2002; Fields et al., 2002). For instance, the linkage and physical maps of the pig genome have devel-oped considerably (for review see Rothschild and Plastow, 1999). These maps have been exploited to search for genes influencing variation in commercially important traits. Sev-eral quantitative trait loci (QTL) scans and candidate gene analyses have identified important chromosomal regions and major genes associated with traits of economic interest in the pig (Milan et al., 2000; reviewed in Bidanel and Rothschild 2002; Fields et al., 2002). It is anticipated that

the developments in genomic technologies will increase the number of markers that can be used in MAS, so that selec-tion for meat quality can be carried out on live animals.

Biochemical Foundation of Meat Quality Research Many pork quality factors (such as water-holding capac-

ity and tenderness) develop as a result of early postmortem biochemical and biophysical processes that occur in mus-cle. Currently, there is a lack of knowledge regarding spe-cifically how and why many variations in tenderness and water-holding capacity develop. In order to have a solid foundation for making decisions that will reduce the varia-tion in meat quality and that will be economically viable, several aspects of fresh meat research need to be grounded in understanding the biochemical processes occurring as muscle is converted to meat. In-depth biochemical studies of early postmortem muscle biology will provide the infor-mation needed to alleviate unforeseen problems that may develop in the future.

Variations in water-holding capacity in fresh pork are ob-served as measurable differences in drip loss or purge. Many recent studies have shown that low water-holding capacity of pork longissimus dorsi may be caused by ge-netic differences other than the Halothane gene or the RN- gene (for review see Cameron, 1990; Knap et al., 2002) . Other research has shown that differences in water-holding capacity also exist between muscles within the same ani-mal. In fact, some studies have observed as much as 35% more product lost as purge in the semimembranosus com-pared to the longissimus dorsi (Lonergan et al., 2001). The specific biochemical and/or biophysical mechanisms of differences in meat water-holding capacity between animals and/or between muscles are not known. One possible ex-planation resides in the structure of the muscle cell itself. As the pH of the muscle declines due to build-up of lactic acid, the intricate latticework of the myofibril within the muscle cell shrinks. If the proteinacous linkages between the myo-fibril and the muscle cell membrane (sarcolemma) are in-tact, this shrinkage can be translated into constriction of the entire muscle cell, thus creating channels between cells and between bundles of cells that can funnel drip (moisture) out of the product. It has been suggested that reduced degrada-tion of proteins that tie the myofibril to the sarcolemma (such as desmin) results in increased shrinking of the muscle cell, which is ultimately translated into drip loss (Kristensen and Purslow, 2001; Melody et al., 2003).

Another aspect of fresh pork quality that is important to the industry is tenderness. A lack of tenderness is one of the most often reported sensory defects in fresh meat. The de-velopment of fresh meat tenderness is associated with pro-teolysis of proteins that make up or are associated with the myofibril (Huff-Lonergan et al., 1996). Since myofibrils make up nearly 80% of the volume of the muscle cell, dis-ruption of these structures will greatly influence meat ten-derness as well as water-holding capacity. As early as 24 hours after slaughter, disruptions in the proteins linking myofibrils to the sarcolemma and to each other can be ob-served (Taylor et al., 1995; Huff-Lonergan et al., 1996).


Other changes that are correlated with increased tenderness include breakages within the myofibrils themselves, particu-larly within the I-band (Davey and Gilbert, 1969; Taylor et al., 1995; Ho et al., 1996). These breakages lead to in-creased fragility and fragmentation of the myofibrils. The increase in myofibrillar fragmentation has been shown to be indicative of the amount of tenderization that has taken place (Culler et al., 1978). These structural changes are the result of proteolysis by endogenous enzymes. One naturally occurring enzyme that is often implicated is the calcium dependent protease µ-calpain. This enzyme not only re-quires the presence of free calcium to be active, but once activated also undergoes autolysis. Autolysis of µ-calpain in fresh meat has often been used to indicate whether calpain has been active.

Microenvironmental factors such as pH and ionic strength appear to influence the ability of calpain to de-grade myofibrillar substrates. As muscle is converted to meat, many changes occur, including: 1) a gradual deple-tion of available energy, 2) a shift from aerobic to anaerobic metabolism favoring the production of lactic acid and re-sulting in the pH of the tissue declining from near neutrality to 5.4-5.8, 3) a rise in ionic strength, in part, because of the inability of ATP-dependent calcium, sodium, and potassium pumps to function, and 4) an increasing inability of the cell to maintain reducing conditions. All of these factors may impact the rate and extent of proteolysis that occur in meat. (Kendall et al., 1993; Huff-Lonergan and Lonergan, 1999). Alterations in pH and/or ionic strengths may cause confor-mational changes that might allow for an increase in hydro-phobicity and lead to aggregation of calpains. Likewise, pH/ionic strength changes may alter the conformation of substrate proteins and render them less susceptible to cleavage by µ-calpain (Huff-Lonergan and Lonergan, 1999).

A slightly accelerated pH decline has been shown to be associated with more rapid attainment of ultimate tender-ness (Marsh et al., 1987; 1988; Hopkins and Thompson, 2002a) and more rapid proteolysis (Rowe et al., 2001; Mel-ody et al, 2003; Hopkins and Thompson 2002b). These conditions have been shown to result in a very limited ag-ing potential. Hypothetically, a rapid pH decline would lead to increased activity of catheptic enzymes and in-creased proteolysis. However, in most cases, this does not seem to occur (Hopkins and Thompson 2002a). Product that has an exceptionally rapid pH decline has been shown to also have limited proteolysis of muscle proteins involved in tenderization (PSE product - Boles et al., 1992; Warner et al., 1997; RSE product – Lonergan et al., 2001a). Low pH values may destabilize µ-calpain and to promote more rapid autolysis and/or activation and subsequent inactiva-tion in in vitro studies (Koohmaraie, 1992) and could do the same in muscle tissue (Rowe et al., 2001).

Therefore, the rate of pH decline may play a very pivotal role in the attainment of ultimate tenderness. The rate of pH decline in addition to ultimate pH should continue to be monitored in future studies that attempt to elucidate the

mechanisms behind the development of tenderness in fresh meat products.

Another change that occurs in postmortem muscle during aging is increased oxidation of myofibrillar proteins (Mar-tinaud et al., 1997) resulting in the conversion of some amino acid residues, including histidine, to carbonyl deriva-tives (Levine, 1984; Martinaud et al., 1997). This can cause the formation of intra and/or inter protein disulfide cross-links (Stadtman, 1990; Martinaud et al., 1997). Both of these changes can reduce the functionality of proteins (Xiong and Decker, 1995). Because calpain enzymes contain both his-tidine and SH-containing cysteine residues at their active sites, they may be particularly susceptible to inactivation by oxidation. Therefore, oxidizing conditions in postmortem muscle may lead to inactivation or modification of calpain activity. Harris et al (2001) showed that meat that had am-ple calcium but higher indices of oxidation actually had an initially slower rate of proteolysis and slower initial rate of tenderization than did product with ample calcium and significantly lower measures of oxidation. There is evidence that suggests oxidizing conditions may reversibly inhibit proteolysis by µ-calpain, but might not inhibit autolysis (Rowe et al., 2003a;2003b; Guttmann et al., 1997;1998). In postmortem muscle, there are differences in the rate that postmortem oxidation processes occur (Martinaud et al., 1997) making this a potentially interesting area to explore.

It is clear that there is a need for more in-depth studies focusing on the early postmortem biology of muscle/meat in order for the industry to make long-range decisions that will reduce the variation and improve the overall quality of pork. The use of protein chemistry, muscle biology and ge-nomic and proteomic tools will have a major impact on discovering the biological mechanisms that underlie the development of meat quality (Huff-Lonergan et al., 2002; Lametsch et al., 2002).

Implementation Below we listed conceivable steps that the pork industry

should consider to guarantee that pork has a fresh appear-ing reddish-pinkish color, is high in water holding capacity, and it is consistently tender and juicy.

1. A greater understanding of perimortem and early postmortem muscle biology is needed to deter-mine the mechanisms underlying the develop-ment of pork quality traits. This will allow the industry to shift from detection of poor quality product to preventing its occurrence;

2. Breeding companies need to fully understand the economic value of meat quality attributes to optimally select for best cost of high quality pork;

3. Precise guidelines should be established and implemented to insure acceptable on-farm pro-duction management and welfare procedures;


4. Pork processing companies should implement statistical process control procedures for pre-slaughter handling and post-slaughter processing to minimize quality variation and develop more robust equipment for on-line measurement of lean quality;

5. Procedures should be put in place to electroni-cally identify and evaluate individual groups of pigs slaughtered for carcass weight, leanness, and quality;

6. Finally, the total value paid for market pigs should reflect accurate value differentials (as dictated by supply-demand forces) between de-sirable and undesirable pork quantity and qual-ity.

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S E N S O R Y E V A L U A T I O N

Utilizing Consumer Data in Product Development

Linda S. Papadopoulos

The most successful products in the market place are born from consumer needs and expectations. These prod-ucts are developed with the end user in mind. Successful products are developed for the consumer, by the consumer. Traditionally, the more innovative or cutting edge the prod-uct is, the more consumer feedback is needed in the prod-uct development process. And once products are devel-oped, consumer feedback is required to keep your products in the lead. While consumer feedback is critical in the con-cept development phase, this paper will focus primarily on the use of consumer feedback on the actual products, not the concept.

Consumer feedback is used throughout the product life cycle. During the product development stage, it is used in these phases:

• In the beginning for concept development and evalua-tion process

• In the middle for prototype building and evaluation • In the final stage for concept/product fit

To minimize product development time and maximize the changes for in-market success, you should start proto-typing only after you have a well-defined, optimized con-cept. Too many times product developers are “shooting in the dark” in what they think the product should be like based on a poorly defined concept. The better defined the concept is, the fewer prototypes will need to be developed, the fewer iterative tests will be done and the greater the chances will be that product will match the concept in the final testing step.

Test the prototypes with the concept early on in the test-ing cycle. Don’t wait until the final go/no go Home-Use Test to test the product with the concept or you might be in for a surprise. Instead, by setting the context in the early

product testing phase by first presenting the concept, you can determine not only the best tasting prototype, but also which prototype best matches the concept. Too often in product testing, the winning prototype is identified but it may or may not match the concept.

Additionally, consumer testing should be done using your target consumer. This is especially true for children’s products. How many times have parents bought or prepared meals for their children assuming that “oh, my kids are go-ing to love this” only to find a half eaten plate of food sitting at the dinner table after everyone has finished eating? We can’t assume that we know what our target consumer is going to like or dislike; we must do our testing among our target consumers in order to achieve reliable results.

Don’t let current manufacturing capabilities or cost con-straints completely limit what you test. Sometimes you have to test prototypes that are outside of your current manufac-turing capabilities or cost parameters in order to better un-derstand what consumers really want in the products. Limit-ing the array of product prototypes often leads to subtle modification of an existing product. However, testing with a wider array helps you identify what consumers truly want in the products as well as the most important elements of these products even if the best prototype is beyond current capa-bility or is too costly to produce. At least the product devel-opers will be able to shoot for a target that they can crea-tively develop against.

To test more efficiently, use experimental design. A sys-tematic approach to product development and product test-ing is a much more efficient manner of understanding what consumers want in the appearance, flavor and texture char-acteristics. By systematically varying the ingredients, the levels or amounts of the ingredients, as well as key aspects of the production process, you can isolate specific factors of the product that drive consumer liking. Consumers are great about telling you if they like or dislike something, but are less able to tell you why. They are even less able to ade-quately rate attributes independently; they often “dump” on several attributes of a given product not because those at-tributes are negative but because they dislike another aspect of the product or the meal. For example, in testing two beef and gravy products made with different gravies but the same meat, consumers will often down rate the texture of

Linda S. Papadopoulos ConAgra Foods, Inc. Six ConAgra Dr. Omaha, NE 68102 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 31-32) June 15-18, 2003, Columbia, Missouri www.meatscience.org


one of the meats because they don’t like the gravy with that meat.

Check the test results for segmentation. Flavor profiles can sometimes be polarizing, which can result in distinct consumer segments. One such example is barbeque sauce; some consumers like a sweet, smoky flavor profile, while others like a more tangy vinegar. In a test conducted with two barbeque sauce samples with each of these flavor pro-files, the sauces may score at parity on overall liking but a closer look at the data would reveal two consumer groups or segments with strong opinions on each sauce. Depend-ing on the size of the segments, launching products targeted to different segments could expand your product offerings.

Identifying the optimum formulation and optimum proc-ess is only part of creating a successful product. Packaging also plays a key role in marketing to the consumer, and in a product’s success. By testing the product with the package with the consumer, you can determine if you have the op-timum packaging. Packaging tests can be done through Central Location tests (CLT’s), Home-Use tests, focus groups or observational research, depending on what it is you want to know about the packaging. Not only does the package convey the perception of quality and food safety, it also offers consumer convenience through easy open features or “cook and serve” features. Observing your target consumers interacting with the package and product can offer valuable insight into how effective the “easy open” features are to use. These observations can also offer valuable insight into how they prepare and eat the products.

Prior to launching a new product, the shelf life must be determined. Sensory shelf life can be determined using trained assessors, consumer panelists, or a combination of both. Trained assessors will be able to detect subtle changes in the sensory attributes that untrained, consumer assessors may not be able to detect and would therefore be the most sensitive tool in protecting product quality. As these changes become more pronounced, the products will need to be assessed by consumers to understand the point at which these changes result in a significant drop in accept-ability.

After the product is launched and is on shelf, the product maintenance phase of the product life cycle begins. In the product maintenance phase, the goal is to gain or sustain a competitive edge. Brand maintenance objectives include ingredient substitutions and formulation/process/package changes. These changes can be for product improvement or cost reduction initiatives.

The specific test method and test parameters are deter-mined by the test objectives. Key points to consider when deciding what and how to test include:

• Should you be testing among your heavy users or the general population? Testing among heavy users is much more sensitive than testing among the general population, which would be preferable in a cost-reduction test. However, product improvements and

category appraisals should be tested among category users.

• Should the test be conducted as a CLT or a Home-Use test? If product preparation will be affected by the re-formulation, a Home-Use test would be advisable. CLT’s are more sensitive in detecting product differ-ences as product preparation, serving order and testing environment is controlled. However, the evaluator does not get to interact with the product during the preparation step.

• How much risk are you willing to assume in being wrong in your conclusions? In a cost-reduction test, the critical error would be in failing to detect that the cost-reduced product is in reality liked less than cur-rent product (Type II error, β). Conversely, the critical error in a product improvement test would be in con-cluding that the revised product is superior to current product when in reality it is not (Type I error, α). Test results showing that products are “not significantly dif-ferent” in overall liking does not mean that the two products are equally acceptable; concluding equal ac-ceptance risks committing a Type II error. Protection against making a Type II error is best addressed through the test design.

• Sample size: how many consumers should you test? That depends on the type of test, objective of the test, how the results will be used, how many samples are in the test, how large of a difference you want to be able to detect and how certain you want to be in the con-clusions. Further discussions on sample size can be found in various sensory reference books (Gacula and Singh, 1984; Lawless and Heymann, 1998).

• How many samples per person? When the number of samples or products in the test exceeds the number of products that can be reasonably evaluated in a given session, the test must either be broken into multiple days, or presented as a balanced, incomplete block design. Depending on the flavor intensity of the prod-uct, the magnitude of the differences among products, and the number of questions on the questionnaire, a good rule of thumb is no more than six products per 1 hr. session.

Consumer feedback is critical not only in the develop-ment phase of a product, but also throughout all phases of a product’s life cycle. Getting consumer feedback early in product development and often throughout the mainte-nance phase will increase the chances of gaining and sus-taining a strong market share.

References Gacula, M.; Singh, J. 1984. Statistical Methods in Food and Consumer

Research. Academic Press, Orlando. FL.

Lawless, H.T.; Heymann, H. 1998. Sensory Evaluation of Food: Principles and Practices. Chapman & Hall, New York, NY.


F O O D S A F E T Y

Current Issues Related to Meatborne Pathogenic Bacteria

John N. Sofos*, Panagiotis Skandamis, Jarret Stopforth & Todd Bacon

Introduction Food animals may be infected, contaminated or be as-

ymptomatic carriers of pathogenic microorganisms and to-gether with the environment they serve as sources of con-tamination for carcasses during the slaughtering process and for meat products during processing, storage and handling, or for water and other foods through contaminated manure (Sofos, 2002a). Foodborne microbial hazards have a devas-tating impact on human suffering because they are esti-mated to cause approximately 76 million cases of illness, 325,000 hospitalizations, and 5,000 deaths in the United States each year (Mead et al., 1999). It is estimated that bac-terial agents are responsible for only 30% of the total food-borne illnesses; however, 72% of total deaths are due to consumption of foods contaminated with bacteria (Mead et al., 1999). The United States National Health Objectives for 2010 aim at reducing the incidence of illness caused mainly by four foodborne pathogens, namely Campylobacter, Sal-monella, Escherichia coli O157:H7 and Listeria monocyto-genes, to 12.3, 6.8, 1.0, and 0.25 cases per 100,000 popu-lation, respectively (DHHS, 2000). According to the latest (2002) surveillance data (CDC, 2003), Salmonella are re-sponsible for causing the highest total number of cases of gastrointestinal illness among bacteria; however, despite the high incidence of illness, the case-fatality rate is <0.05%. Campylobacter is responsible for the second highest total number of gastrointestinal illnesses and like Salmonella, it has a case-fatality rate of <0.05% (CDC, 2003). Although E. coli O157:H7 has a much lower rate of incidence com-pared to Salmonella and Campylobacter, this organism has a higher case-fatality rate (0.1%). Compared to the above-mentioned pathogens, L. monocytogenes has the lowest rate of incidence but a significantly higher (approximately 20%) fatality rate (Mead et al., 1999). Thus, there is a need to control pathogenic microorganisms in animals and their

products in order to enhance the safety of our meat supply.

An outbreak of E. coli O157:H7 in the western United States in 1992-1993 was attributed to consumption of un-dercooked ground beef patties and led to development of illness in several hundred people and four deaths (Bell et al., 1994). This highly publicized outbreak may be consid-ered as the beginning of intensified public scrutiny on food safety that has led to major developments, including the complete change of the United States meat inspection sys-tem, which was in place since the early 1900s. The new United States Meat and Poultry Inspection Regulation was published in 1996 (FSIS, 1996) and requires federally in-spected meat and poultry plants: (1) to establish sanitation standard operating procedures to serve as a foundation in meat processing; (2) to implement the hazard analysis criti-cal control point (HACCP) system of process control (NACMCF, 1998); and, (3) to apply performance criteria in the form of microbial testing for Escherichia coli counts and Salmonella incidence as criteria of HACCP verification and pathogen reduction, respectively (FSIS, 1996; Sofos, 2002a; Sofos and Smith, 1998; Sofos et al., 1999). Furthermore, publicity over food safety issues has led to the establishment of national food safety initiatives such as: (1) the United States National Food Safety Initiative and associated pro-grams or activities such as the FoodNet® and PulseNet® foodborne illness surveillance networks; (2) the FightBac® and Thermy® educational programs; (3) emphasis on risk assessment studies and evaluations; and, (4) an increase in federal funding for food safety research and education is-sues (http://www.foodsafety.gov).

The following sections provide brief information on gen-eral characteristics of the bacterial pathogens of most con-cern in recent years (Bacon and Sofos, 2003), brief summa-ries of current research activities and interventions to con-trol bacterial pathogens in meat products, and an introduc-tion to certain concerns associated with efforts to control pathogens.

Characteristics of Bacterial Pathogens Escherichia coli O157:H7: Escherichia coli are mostly

harmless natural colonizers of the gastrointestinal tract of humans and other warm-blooded animals; however, patho-genic E. coli strains exist and are associated with syndromes

J.N. Sofos Department of Animal Sciences, Room 7B Colorado State University Fort Collins, Colorado 80523-1171 USA E-mail: [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 33-37) June 15-18, 2003, Columbia, Missouri www.meatscience.org


of diarrheal illness (Bacon and Sofos, 2003). Strains produc-ing Shiga-like toxins (SLT), also known as verotoxins (VT), are associated with hemorrhagic colitis and hemolytic ure-mic syndrome in humans and are regarded as enterohemor-rhagic E. coli (EHEC). The predominant EHEC serotype as-sociated with foodborne illness is E. coli O157:H7. Es-cherichia coli O157:H7 are gram-negative, facultatively anaerobic, nonspore-forming rods that are mostly motile, and grow at temperatures ranging from 7 to 46°C, with an optimum between 35 and 40ºC. Escherichia coli O157:H7 require a water activity (aw) of at least 0.95 and are able to grow in the presence of 6.5% sodium chloride. Although they grow best at pH 6.0 to 7.0, they can also grow at pH 4.4 to 9.0 and, unlike most foodborne pathogenic bacteria, they are tolerant to acidic environments. Illness associated with E. coli O157:H7 results through fecal-oral transmission by contaminated hands or consumption of contaminated foods or water. Between 1993 and 1998, most (72%) of the E. coli O157:H7 outbreaks were foodborne and of the foods implicated in the outbreaks, beef was responsible for 45% of the cases and 90% of the time the beef product was ground. Following ingestion (>101 cells) and a 3 to 9 day incubation period, E. coli O157:H7, can cause a wide range of symptoms including mild or severe bloody diarrhea (hemorrhagic colitis), hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) (Bacon and Sofos, 2003).

Listeria monocytogenes: They are nonspore-forming, aerobic, microaerophilic or facultatively anaerobic, gram-positive rods that are motile by means of peritrichous fla-gella (Bacon and Sofos, 2003). This organism is ubiquitous in the environment and is harbored in approximately 11 to 52% of animals. Listeria monocytogenes has become a con-cern to the industry as it has been isolated from an exten-sive range of meat plant environments including floors, drains, condensed and standing water, and food residues on processing equipment. It is notable that L. monocytogenes forms resistant biofilms on equipment surfaces under condi-tions of limited nutrient availability. Listeria monocytogenes have also been isolated from <1-70% of whole and proc-essed red meats, up to 60% of ready-to-eat poultry and 80 to 90% of raw or processed poultry. Listeria monocytogenes is psychrotrophic and can grow at temperatures as low as –0.4°C and up to 45°C (optimum of 30 to 37°C). Growth of L. monocytogenes occurs in environments of pH 4.4 to 9.4, at aw levels above 0.92, and survives at sodium chloride levels of up to 30%. Listeriosis is mainly an infection of the central nervous system (meningitis and meningoencephali-tis), bacteremia and resulting in stillbirth, fetal death or spontaneous abortion in pregnant woman. The infectious dose of listeriosis is speculated to be as low as 100 cells/g, and the illness has an incubation period of a few days to 2 to 3 months (Bacon and Sofos, 2003).

Salmonella: They are gram-negative, facultatively an-aerobic, nonspore-forming rods. The only two species rec-ognized are S. enterica, possessing six subspecies, and S. bongori. There are approximately 2,600 Salmonella sero-

types of which S. Typhimurium and S. Enteritidis are the most prevalent in the U.S. (Bacon and Sofos, 2003). Salmo-nella can grow at temperatures as low as 5.2 and as high as 46.2°C, pH values of 3.8 to 9.5, and at aw levels above 0.93. The primary reservoir for Salmonella is the intestinal tract of infected hosts or carriers, where cells are subse-quently sloughed and excreted in the feces. Nontyphoidal Salmonella strains usually cause gastroenteritis after an in-cubation period of 5 h to 5 days resulting in diarrhea, nau-sea, mild fever, chills, vomiting and abdominal cramping. Infectious doses of salmonellae may range from as low as 100 to 103, depending on the serotype, vehicle of transmis-sion and on the individual’s immune system (Bacon and Sofos, 2003).

Campylobacter jejuni: They are gram-negative nonspore-forming rods that are slender and curved, which along with the single, polar flagellum located at one or both ends con-tributes to the organism’s characteristic “corkscrew-type” motility (Bacon and Sofos, 2003). The bacterium is mi-croaerophilic, growing best in environments with 2.0 to 5.0% oxygen and 5.0 to 10.0% carbon dioxide, while growth is inhibited in the presence of 21% oxygen. The temperature and pH ranges for growth of C. jejuni are 30 to 45°C (optimum 37 to 42ºC) and 4.9 and 8.0 (optimum 6.5 to 7.5), respectively. Campylobacter jejuni are sensitive to salinity (>0.5% sodium chloride), drying (require aw above 0.912), freezing, heat and acidic conditions (< pH 5.0). Campylobacteriosis may result from as few as 500 viable cells and infection typically requires 2 to 10 days before onset of gastroenteritis-associated symptoms. Infection typi-cally involves acute colitis combined with fever, malaise, abdominal pain, headache, watery or sticky diarrhea with minor traces of blood (occult), inflammation of the lamina propria, and crypt abscesses. Infection may result in further sequelae, the most severe including the acute paralytic dis-ease of the peripheral nervous system known as Guillain-Barre syndrome and Reiter’s syndrome (autoimmune dis-ease caused by infection) (Bacon and Sofos, 2003).

Other Meatborne Bacterial Pathogens: Several other bac-terial pathogens are associated with meat and poultry prod-ucts but their contribution to foodborne disease has been overshadowed by the impact of the above-mentioned four pathogens in recent years. They include Yersinia enterocoli-tica, Staphylococcus aureus, Clostridium botulinum, Clos-tridium perfringens, and Bacillus cereus. For more informa-tion on these and other pathogens see Bacon and Sofos (2003).

Current Approaches to Bacterial Pathogen Control in Meat Products

The increasing prevalence of pathogens, such as E. coli O157:H7, on animals before slaughter in recent years (Elder et al., 2000) necessitates employment of interventions for their control. In its efforts to promote control of the inci-dence of E. coli O157:H7 and other pathogens in meat, the FSIS/USDA has been enforcing a zero tolerance policy for


visible soil on carcasses during slaughter and has declared E. coli O157:H7 an adulterant in fresh ground beef and other non-intact fresh beef cuts (http://www.fsis.usda.gov). Testing of fresh beef for this pathogen has resulted in sev-eral, highly publicized, product recalls from the market-place. All segments, including, regulators, educators, con-sumers, health authorities, research scientists and the indus-try agree that efforts should be made to reduce incidence and eliminate or control pathogenic bacteria at all stages of the food chain (Sofos, 2002a). The producers of food ani-mals in the United States have contributed to the overall effort of improving food safety by supporting development and applying quality assurance programs and by financially supporting, through their associations, research and devel-opment studies on microbial reduction and pathogen con-trol interventions applied during animal slaughter and meat processing. The meat processing industry has also under-taken initiatives and efforts to comply with consumer de-mands for food safety, customer specifications or criteria, and regulatory requirements included in the new meat and poultry inspection regulations (FSIS, 1996). The target of the meat processing industry has been to improve operations through implementation of HACCP programs, and employ-ment of various carcass decontamination or pathogen con-trol interventions.

A variety of processes have been developed with the ob-jective of reducing contamination on carcasses. Decon-tamination processes include animal cleaning, chemical dehairing at slaughter, spot-cleaning of carcasses before evisceration by knife-trimming or steam and vacuum, spray-ing, rinsing, deluging or dipping of carcasses before evis-ceration and/or before chilling with water or chemical solu-tions (e.g., organic acids, acidified sodium chlorite, per-oxyacetic acid-based products, trisodium phosphate, etc.) or steam. These interventions are applied at various concen-trations or intensities, pressures (2-20 bar), temperatures (15-80°C) and for different lengths of time (5-20 sec), indi-vidually or in sequential combinations. Decontamination interventions are used extensively in the United States and they are integrated into food safety management systems, such as HACCP, which, as indicated, is required by regula-tion (Bacon et al., 2000; Smulders and Greer, 1998; Sofos and Smith, 1998). Most processors of fresh meat in the United States may employ more than one decontamination intervention, in sequence, and this "multiple hurdle" ap-proach to decontamination should result in microbiologi-cally cleaner carcasses and may assist plants in meeting regulatory requirements (Bacon et al., 2000; Sofos et al., 1999). Thus, application of decontamination processes should contribute to the enhancement of product safety, provided that chilling, cutting, processing, storage, distribu-tion and preparation for consumption are also performed properly and under hygienic conditions. It is important to realize, however, that control or management of food safety risks should be based on an integrated effort and approach that addresses all sectors, from the producer through the packer, processor, distributor, retailer, food service worker and consumer. Reduction of pathogen prevalence on ani-

mals pre-harvest may lead to a reduced probability that errors occurring in subsequent parts of the food chain will lead to foodborne illness. Additional interventions to help in enhancing food safety or to eliminate pathogens in ready-to-eat meat products are applied during processing and in-clude heating, chilling, freezing, drying, fermentation, use of chemicals as acidulants or antimicrobials, packaging, proper storage and distribution, and appropriate handling and preparation for consumption. Indeed, food safety assur-ance involves activities and responsibilities throughout the food chain.

Recently the FSIS/USDA (http://www.fsis.usda.gov) has issued directives, notices and guidances for meat operations to consider E. coli O157:H7 a food safety hazard that is reasonably likely to occur in fresh beef. Thus, they should re-evaluate their HACCP plans and establish plant-validated control measures (FSIS Directive 10,010.1/February 1, 1998; FSIS Notice 44-02/November 4, 2002; Proposed FSIS Directives in Federal Register October 7, 2002/Volume 67, Number 194, Pages 62-325-62334; FSIS Guidance for Minimizing the Risk of Escherichia coli O157:H7 and Sal-monella in Beef Slaughter Operations; FSIS Guidance for Beef Grinders and Suppliers of Boneless Beef and Trim Products).

In addition to E. coli O157:H7, L. monocytogenes has become a major concern for the meat processing industry worldwide. Following a listeriosis outbreak in the United States in 1998-1999, which caused 21 deaths and at least 100 illnesses in 14 states due to consumption of post-processing contaminated hot dogs and luncheon meats (CDC, 1999), L. monocytogenes has re-emerged as a meat-borne pathogen of concern in the United States. Another listeriosis outbreak in 2002 caused 50 illnesses, 7 deaths and 3 miscarriages in 8 northeastern states of the United States and was associated with consumption of contamina-tion ready-to-eat poultry products (CDC, 2002). These fatal outbreaks and the frequent and highly publicized recalls of meat products potentially contaminated with the pathogen have alerted the industry, public health authorities and re-searchers to develop and establish effective measures and procedures to maintain product safety and increase con-sumer confidence in ready-to-eat meat products (Bernard and Scott, 1999; Tompkin, 2002; Tompkin et al., 1999). Results of our studies have shown that use of modified marinades in the form of multiple hurdles are effective in enhancing destruction of pathogenic bacteria during drying of meat products as well as post-drying contaminants during product (i.e., beef jerky) storage (Calicioglu et al., 2002a,b, 2003). Inclusion of antimicrobials (acetates, diacetates, lac-tates, benzoates, sorbates, glucono-delta-lactone, and their combinations at reduced concentrations) in the formulation or their application as dipping solutions after product slicing and before packaging were found effective in controlling L. monocytogenes in ready-to-eat cured meat products con-taminated after cooking (Bedie et al., 2001; Samelis et al., 2001a, 2002a).


For ready-to-eat meat and poultry products, the FSIS/USDA has proposed the following performance crite-ria: (1) a 6.5 log reduction of Salmonella during processing of ready-to-eat meat products; (2) a 7.0 log reduction of Salmonella during processing of ready-to-eat poultry prod-ucts; (3) a 5.0 log reduction of E. coli O157:H7 during processing of fermented meat products containing beef; (4) no more than 1.0 log growth of Clostridium perfringens and no growth of Clostridium botulinum during cooling of all ready-to-eat meat products (hhtp://www.fsis.usda.gov). Relative to control of L. monocytogenes in ready-to-eat meat and poultry products, the USDA/FSIS has published a directive (10,240.3/December 9, 2002) titled Microbial Sampling of Ready-To-Eat (RTE) Products for the FSIS Verifi-cation Testing Program.

Potential Concerns Associated with Bacterial Patho-gen Control Approaches

As they have done in the past, microorganisms continue to evolve and their large genetic variability and short gen-eration times increase their potential for survival in less than favorable environments. The emergence of resistant bacteria as a result of the ubiquity of antimicrobials in their envi-ronment, has led to public health concerns centered around increased morbidity and mortality associated with failing antimicrobial treatments (Bacon et al., 2002). In addition to the emergence of antibiotic resistance, common foodborne pathogenic bacteria have demonstrated resistance and cross-protective capabilities to food preservation stresses as well as increased virulence. The induction of bacterial resis-tance to environmental stresses such as temperature and pH extremes involves the production of “protective” shock pro-teins, some of which possess cross-protective capabilities, or the ability to confer protection to more than one type of stress. Recent and continuing research efforts in our labora-tory have focused on potential food safety risks and critical control points concerning stress-adapted pathogens (Samelis et al., 2001b,c, 2002b,c; Stopforth et al., 2002, 2003). It was shown that E. coli O157:H7 has greater potential to survive in organic acid (more so in acetic than lactic acid) beef decontamination runoff fluids (washings) compared to L. monocytogenes and S. Typhimurium, even with moderate previous acid-adaptation (Samelis et al., 2001b). Acid-adaptation was shown to enhance survival of E. coli O157:H7 for up to 14 d in mixtures of both acetic and lac-tic acid (2%) washings mixed with water washings at ratios of 1:1, 1:9 or 1:99 (Samelis et al., 2002b). In addition, it was shown that acid-adaptation of E. coli O157:H7 negatively influenced the pathogen’s ability to readapt to a sudden shift to higher pH (6.5 to 7.5) conditions of beef water washings (Samelis et al., 2002b). Results have demonstrated that acid decontamination interventions may alter the mi-crobial ecology of meat plant environments (Samelis et al., 2002b; Stopforth et al., 2003), selecting for the growth and attachment to equipment surfaces of the natural meat flora and may enhance the survival of attached pathogens fol-lowing long-term stressing (Stopforth et al., 2003). In gen-

eral, exposure to sublethal stress during food processing may result in stress-hardened pathogens surviving more readily subsequent antimicrobial treatment applications aimed at improving microbiological food quality, poten-tially resulting in persistent microbiological populations possessing elevated virulence factor expression (Samelis and Sofos, 2003; Sheridan and McDowell, 1998; Sofos, 2002b). Overall, however, interventions for decontamina-tion of carcasses are useful because they reduce levels of contamination and allow plants to meet regulatory perform-ance criteria and standards as well as contractual specifica-tions for product contamination. Evidence indicates that these interventions cause major reductions in prevalence of pathogens such as E. coli O157:H7 (Elder et al., 2000). It should be noted, however, that these interventions are gen-erally instantaneous or of short intensity and inadequate for complete microbial inactivation or removal. Issues such as those associated with microbial penetration in muscle tis-sues, biofilm formation, bacterial sublethal injury, alteration of metabolic activity potentially resulting in development of stress adaptation and cross protection, and changes in meat and plant environment microbial association need to be considered. As we develop knowledge to better understand these concerns, we will be able to select and apply inter-vention treatments of optimum intensity and in a sequence that maximize antimicrobial effects.

Overall, the microbiological status of the products that reach the consumers, either as raw meat or processed prod-ucts, will depend on exposure to contamination and its con-trol during all steps of the food production, processing, dis-tribution, storage, retailing and preparation for consumption chain. Proper application of the processes described above will yield products that should be safe for consumption fol-lowing proper cooking and/or serving.

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Bacon, T.R.; Sofos, J.N.; Belk K.E.; Hyatt, D.R.; Smith, G.C.. 2002. Preva-lence and antibiotic susceptibility of Salmonella isolated from beef animal hides and carcasses. Journal of Food Protection 65:284-290.

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Bell, B.P.; Goldoft, M.; Griffin, P.M.; Dans, M.A.; Gordon, D.C.; Tarr, P.J.; Bartleson, C.A.; Lewis, J.H.; Barret, T.J.; Wells, J.W.; Baron, R.; Kobaya-shi, J. 1994. A multistate outbreak of Escherichia coli O157:H7- associ-ated bloody diarrhea and hemolytic uremic syndrome from hamburg-ers, the Washington experience. Journal of the American Medical Asso-ciation. 272:1249-1353.

Bernard, D.T.; Scott V.N. 1999. Listeria monocytogenes in meats: New strategies are needed. Food Technology 53:124.


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Calicioglu, M.; Sofos, J.N.; Samelis, J.; Kendall, P.A.; Smith, G.C. 2002a. Inactivation of acid-adapted and nonadapted Escherichia coli O157:H7 during drying and storage of beef jerky treated with different marinades. Journal of Food Protection 65:1394-1405.

Calicioglu, M.; Sofos, J.N.; Samelis, J.; Kendall, P.A.; Smith, G.C. 2002b. Destruction of acid- and non-adapted Listeria monocytogenes during drying and storage of beef jerky. Food Microbiology 19:545-559.

Samelis, J.; Sofos, J.N.; Kain, M.L.; Scanga, J.A.; Belk, K.E.; Smith, G.C. 2002a. Control of Listeria monocytogenes with combined antimicrobi-als following post-process contamination and extended storage of frankfurters at 4°C in vacuum packages. Journal of Food Protection 65:299-307. Calicioglu, M.; Sofos, J.N.; Kendall, P.A. 2003. Fate of acid-adapted and

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Samelis, J.; Sofos, J.N.; Ikeda, J.S.; Kendall, P.A; Smith, G.C. 2002c. Expo-sure to water meat decontamination washing fluids sensitizes Es-cherichia coli O157:H7 to organic acids. Letters in Applied Microbiol-ogy 34:7-12.

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Foods). 1998. Hazard Analysis and Critical Control Point Principles and Application Guidelines. Journal of Food Protection 61:762-775. Stopforth, J.D.; Samelis, J.; Sofos, J.N.; Kendall, P.A.; Smith, G.C. 2002.

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F O O D S A F E T Y

Postharvest Pathogen Interventions for Meat and Poultry

Fred W. Pohlman* & Kathy S. McElyea

Introduction Although progress has been made in regard to pathogen

reduction technologies, the incidence and retardation of pathogens in the meat supply remains a high priority. As examples, on October 7, 2002, the Food Safety and Inspec-tion Service (FSIS) issued a notice in the Federal Register mandating HACCP reassessments for E. coli O157:H7 and indicated that testing exemptions would furthermore be revoked. As promised, and due to the “E. coli summer sea-son,” on April 18, 2003, the FSIS issued Notice 11-03 indi-cating that the FSIS will begin sampling raw ground prod-ucts for E. coli O157:H7 at all grinding facilities, regardless if an establishment was previously exempt from routine sampling, in effect removing all exemptions. To this end, in-plant inspectors will receive sampling request forms and draw samples regardless of the plants own testing program.

Therefore, the use of decontamination methods for meat remains important to ensure the safety of muscle foods. Long recognizing the importance of these technologies, substantial research has focused on development of antim-icrobial interventions. Antimicrobial interventions re-searched for meat have included various organic acids and their salts, chlorinated compounds, quaternary ammonia-like compounds, various buffers, rinses, ozone/oxidizers, hot water, steam pasteurization and vacuum, chelators and baceriocins to name a few. Reductions from these tech-nologies have ranged from less than one log10 (log) reduc-tion to several log reductions depending on efficacy of the treatment and initial microbial loads before treatment. To this end, a number of these technologies are currently being used in the meat industry to improve meat safety. However, the vast body of these technologies have been researched, developed and implemented for carcass decontamination

applications. While these technologies either are or have the potential for reducing pathogens in the meat supply, a substantial opportunity for pathogen reduction exists post-harvest. While carcass interventions are an important part of a concerted intervention strategy, they do not render the carcass sterile. Therefore, subsequent fabrication where cuts are exposed to conveyor belts, knives, human hands etc. through the normal course of fabrication expose meat cuts to cross and recontamination vectors which therefore may not lead to microbial reductions in final products. There-fore, substantial opportunity exists to not only decontami-nate carcasses but also decontaminate cuts and meat pieces postharvest, closer to the packaging phase to provide mi-crobial reductions that can be achieved in the final package selected by the consumer. With either the postharvest or carcass then postharvest intervention strategies in a multiple intervention approach, it is only recently that research has addressed these types of applications. However, a wealth of knowledge can be gleaned from past carcass intervention research, particularly where muscles were excised then treated with various antimicrobial interventions. While these studies focused on applying the reductions achieved on excised tissues back to the carcass, they certainly could have applications forward to retail cuts or trimmings des-tined for ground beef and lead to reductions in pathogens in the meat supply directly purchased by the consumer.

Postharvest interventions for beef cuts or tissues While substantial research has been conducted on mi-

crobial interventions for carcasses, less work has been con-ducted and published on postharvest interventions. How-ever, a number of carcass intervention studies have used excised tissue to test antimicrobial effectiveness and al-though the focus was for carcass decontamination, these carcass decontamination technologies might have applica-tion for retail cuts or ground beef. For studies where tissue was excised and treated with antimicrobial interventions, one can get a sense of how these technologies might per-form on primals, subprimals, retail cuts or trimmings, if that was their intended application. Therefore, for brevity, this paper reviews only selected tissue studies and not carcass applications for direct reductions in microorganisms. Like-wise, for brevity, irradiation, although a postharvest patho-gen reduction technology, is also not discussed.

Fred W. Pohlman University of Arkansas Department of Animal Science B103D AFLS Bldg. Fayetteville, AR 72701 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 39-47) June 15-18, 2003, Columbia, Missouri www.meatscience.org


Table 1 illustrates selected studies for postharvest patho-gen reductions on beef cuts or tissues, beef trimmings des-tined for ground beef and direct ground beef interventions. This table also shows possible ranges for microbial reduc-tions with the use of these individual interventions. Numer-ous technologies have been researched for the reduction of microorganisms on beef tissues. Organic acids such as lac-tic acid, acetic acid, formic acid, citric acid and gluconic acid have shown abilities to reduce E. coli, coliforms, aero-bic bacteria and Salmonella spp. However, like other inter-vention technologies, organic acids have shown variability in their ability to reduce microbial loads. These variations can sometimes be explained by concentrations, duration of application, application techniques, microbial load or mi-crobial resilience, but substantial unexplained variation still exist. Lactic acid has been observed to reduce E. coli on beef tissue by 0.2 log (Kotula and Thelappurate, 1994) up to greater than 3 log reductions (Dorsa et al., 1998a). In addi-tional studies some enhancement in microbial reduction, including E. coli reduction might be accomplished by heat-ing organic acids before application to beef tissue (Ander-son and Marshall, 1990a,b; Anderson et al., 1979). With coliforms, a common fecal bacterial contaminant, lactic acid has shown reductions from 0.6 log to greater than 1 log reduction (Anderson and Marshall, 1990b). Aerobic bacteria are also susceptible to lactic acid treatments and can be reduce from 0.8 (Anderson and Marshall, 1990b) to greater than 2 log reductions (Dorsa et al., 1997). Salmo-nella has also shown a similar susceptibility response to lactic acid as E. coli with reductions from 0.7 log to greater than 3 logs possible (Dorsa et al., 1998a). Acetic acid has produced similar microbial reductions as lactic acid. Using acetic acid on beef shortloins, Bala et al. (1977) was able to reduce E. coli in excess of 3 logs. Furthermore, Dickson (1991) was able to reduce Salmonella typhimurium on beef trimmings by up to 3 logs using acetic acid.

Other organic acids tested on beef tissue have included formic (Bell et al., 1986), citric (Brackett et al., 1994) and gluconic (Garcia-Zepeda et al, 1994) acids. In general, these have not shown the same effectiveness for maximum microbial reductions on beef tissues or cuts as lactic and acetic acids, although they have not been as widely re-searched. Microbial reductions reported have generally been below 1 log for any given microorganism using these organic acids.

Another approach for using organic acids has been mul-tiple organic acid mixtures (Anderson and Marshall, 1990a; Goddard et al., 1996). However, in limited studies, mixtures of organic acids seem to yield similar microbial reductions as single organic acid applications (Table 1).

Sodium hypochlorite and hypochlorous acids have also been evaluated on beef tissue for aerobic bacteria reduc-tion. Aerobic bacteria reductions have been reported be-tween 0.2 log and 1.0 log (Anderson et al., 1979; Johnson et al., 1979).

One of the most effective antimicrobial inhibitors in beef tissue reported has been cetylpyridinium chloride (CPC), a compound commonly found in oral hygiene products. Cut-ter et al. (2000) reported up to 6 log reductions to virtually undetectable levels for E. coli and Salmonella on beef lean when beef shortplates and cutaneous trunci muscles were treated with 1% CPC. Another compound, which has shown abilities to reduce microorganisms on beef tissue, is trisodium phosphate (TSP). Dorsa et al. (1998a) reported trisodium phosphate reduced E. coli and Salmonella typhi-murium by greater than 4 logs on beef neck tissue.

Other interventions such as cold water and hot water rinses have also been evaluated for reducing microorgan-isms on beef tissues. In general and as expected, hot water has often produced higher microbial reductions than cold water. Reductions up to and in excess of 2 logs have been reported for aerobic plate counts (APC), E. coli, and Salmo-nella spp. using hot water rinses (Anderson et al., 1979; Dorsa, 1998a). In addition to water, steam has also been evaluated on beef tissues for microbial reduction. However, although there has been substantial research conducted with steam on beef carcasses, surprisingly little data has been reported for the use of steam in postharvest applica-tions. In one study, Anderson et al. (1979) reported only 0.1 log reduction in APC using steam, however, based on car-cass research, it would appear likely that substantially greater microbial reductions could be achieved using steam applications postharvest. In other work, instead of chemical interventions, Pohlman et al. (1997) had some effect on aerobic bacteria reduction on beef muscle using low inten-sity ultrasound.

An area that may hold promise regarding maximum mi-crobial reductions might be the use of multiple antimicro-bial interventions at multiple stages of production. The use of “hurdle” technology may show particularly advantageous benefits should the most effective antimicrobials be utilized in a multiple intervention approach. Utilizing multiple in-terventions, Kang et al., (2001a and 2001b) and Kondaih et al. (1985) demonstrated that it is possible to reduce patho-gens and aerobic bacteria in excess of 2 logs on beef tissue.

Postharvest interventions for beef trimmings destined for ground beef

While the safety of beef cuts remains a concern, perhaps more importantly is the safety of ground beef. Because ground beef is often produced from beef trimmings from numerous animals and because of grinding and mixing op-erations, which more equally distribute any microorganisms present as well incorporating air, the potential for ground beef to harbor pathogens remains a concern. Therefore, decontamination of trimmings before grinding or of ground beef post grinding might be advantageous to reduce micro-bial loads in ground beef. These postharvest applications have only been recently explored.

Using cold or hot water on beef trimmings before grind-ing has been shown to reduce E. coli and Salmonella typhi-


murium by up to 2 logs in ground beef (Dorsa et al., 1998a; Ellebracht et al., 1999 and Stivarius et al., 2002)(Table 1). Additionally, lactic and acetic acid treatments have also been used to decontaminate beef trimmings before grinding (Stivarius et al., 2002a; Conner et al., 1997 and Dorsa et al., 1998a) and have achieved E. coli and Salmonella typhi-murium reductions by up to 3 logs in ground beef. Using gluconic acid and trisodium citrate, Stivarius et al. (2002b) reduced E. coli, Salmonella typhimurium, coliforms and aerobic bacteria in ground beef by less than 1 log. How-ever, Stivarius et al. (2002c) reported slightly greater reduc-tions for these same microorganisms in ground beef using chlorine dioxide or ozonated water wash of beef trimmings before grinding.

Although ground beef is one of the most difficult meat products to reduce microorganisms in, trisodium phosphate has been demonstrated to reduce E. coli, Salmonella typhi-murium, coliforms and aerobic bacteria in ground beef when applied to beef trimmings (Pohlman et al., 2002b; Dorsa et al., 1998a; Dorsa et al., 1998b). Reductions in E. coli in ground beef in excess of 2 logs and Salmonella ty-phimurium in excess of 3 logs has been observed from treated trimmings. Another intervention, cetylpyridinium chloride, used on beef trimmings before grinding, has been reported to reduce E. coli, Salmonella typhimurium, coli-forms and aerobic bacteria in ground beef by <1 log (Pohlman et al., 2002b). These findings illustrate the diffi-culty for reducing microorganisms in ground beef when compared to reductions in microorganisms on beef tissue when comparing up to a 6 log reduction when cetylpyridin-ium chloride was used on beef tissue surfaces (Cutter et al., 2000).

Interestingly, using multiple “hurdle” interventions on beef trimmings prior to grinding has been shown to be more effective for reducing microorganisms in ground beef than its single intervention counterparts. In a series of studies (Pohlman et al., 2002b; Pohlman et al., 2002c) showed re-ductions in E. coli, Salmonella typhimurium, coliforms and aerobic bacteria in ground beef up to and in excess of 2 logs when multiple interventions were applied to beef trimmings before grinding. Therefore, the use of multiple or “hurdle” technology might show promise for the safety im-provement of ground beef.

In addition to treatment of beef trimmings before grinding to improve ground beef safety, a number of direct additives or technologies have been applied to ground beef. Ajjarapu and Shelef (1999) found that the addition of sodium lactate or diacetate to ground beef delayed growth of E. coli in storage. Likewise, Meca et al. (1997) reported that direct addition of sodium acetate reduced aerobic bacteria in ground beef from 0.1 to 0.6 logs and that buffered cit-rate/sodium citrate reduced APC by up to 0.2 logs. Egbert et al. (1992) found that potassium lactate reduced coliforms by up to 1 log and aerobic bacteria by up to 0.8 log in ground beef. An additional technology for reducing pathogens in ground beef is that of hydrostatic pressure. Using hydro-

static pressure, Carballo et al. (1997) was able to reduce E. coli in ground beef by up to approximately 2 logs.

Postharvest interventions for poultry, pork & lamb As with beef, much of the published research regarding

microbial interventions for poultry, pork and lamb has in-volved carcass decontamination. While the industry has done substantial research on postharvest interventions, less peer-reviewed research is available. This is particularly true for poultry with much of the work involving chill decon-tamination of carcasses. Additionally, due to the small car-cass size and rapid fabrication rates, it is also likely that this has lead to a history of more carcass decontamination work and less postharvest decontamination research. However, it is apparent that the poultry industry also recognizes the benefits that postharvest decontamination may provide. Since many of the same interventions as beef have been attempted on poultry, Table 2 shows examples of selected postharvest interventions for poultry, pork and lamb as well as a some additional interventions researched on poultry carcasses not previously discussed.

Using acidified sodium chlorite, Kemp et al. (2001) was able to reduce E. coli, Salmonella spp. and Campylobacter spp. on chicken carcasses by 2.3, 2.0 and 2.6 logs, respec-tively. Additionally, Kemp et al. (2000) found that acidifying with citric acid gave substantially better microbial reduc-tions than acidifying with phosphoric acid. Trisodium phos-phate, lactic acid, cetylypyridinium chloride and sodium bisulfate have also been researched for reducing microor-ganisms on poultry (Yang and Slavik, 1988; Lillard, 1994; Wang et al., 1997; Breen et al., 1997 and Xiong et al., 1998). Reductions in aerobic bacteria up to 4.9, 1.8, 2.3 and 1.7 logs have been reported for trisodium phosphate, lactic acid, cetylypyridinium chloride and sodium bisulfate, respectively. For postharvest interventions, Hwang and Beuchat were able to reduce Salmonella spp., Campylobac-ter spp., L. monocytogenes, S. aureus and E. coli by 2.5, 1.0, 0.5, 1.5, and 1.3 logs, respectively on chicken wings using lactic acid and sodium benzoate.

In other poultry postharvest research, hydrostatic pressure has been used to reduce pathogens and microorganisms in ground chicken and various meat models. Hydrostatic pres-sure up to 700MPa has been reported to reduce Listeria spp., Salmonella spp., E. coli and S. aureus by up to 7.5, 2.0, 6.0 and 6.0 logs, respectively in ground poultry (Patter-son et al., 1995; Patterson et al., 1998; Yuste et al., 1999).

Postharvest decontamination of turkeys has also seen re-search activity. Kalinowski and Tomkin (1999) were able to reduce Clostridium spp. on turkey breast cores by up to 0.8 logs using sodium diacetate or a combination of sodium lactate and sodium diacetate. Whereas Schlyter et al. (1993) was able to reduce L. monocytogenes in ready to eat turkey breasts by up to almost 5.0 logs using combinations of sodium lactate, diacetate and nitrate. However, Schlyter et al. (1993) found the greatest reductions in L. monocytogenes occurred when pedio-cin was combined with sodium diacetate.


Table 1. Selected postharvest interventions for beef tissue, cuts or in ground beef.

Antimicrobial Microorganism Inhibition (logs) Reference

Beef cuts/tissues

Lactic acid Ambient or heated

E. coli Coliforms APC S. typhimurium

0.2-3.1 0.6-1.1 0.8-2.5 0.7-3.0

Anderson & Marshall, 1990b; Brackett et al., 1994; Kotula & Thelappurate, 1994; Dorsa et al., 1998a; Dorsa et al., 1997

Acetic acid Ambient or heated


0.3-3.2 0.7-1.75 1.1-3.4 0.5-3.0

Anderson & Marshall, 1989; Anderson et al., 1979; Bala et al., 1977; Bell et al., 1986; Brackett et al., 1994; Dickson, 1992; Dickson, 1991; Dickson & Siragusa, 1994; Kotula & Thelappurate, 1994; Dorsa et al., 1998b; Dorsa et al., 1997

Formic acid E. coli Coliforms S. typhimurium

<1.0 <1.0 <1.0

Bell et al., 1986

Citric acid E. coli <0.3 Brackett et al., 1994

Gluconic acid Psychrotrophs

Lactic acid bacteria 0.2-0.5

0.7 Garcia-Zepeda et al., 1994

Mixed organic acids Ambient or heated


0.4-0.9 0.7-1.6 0.6-1.7 0.8-1.7

Anderson & Marshall, 1990a; Goddard et al., 1996

Sodium hypochlorite/ Hypochlorous acid APC 0.2-1.0 Anderson et al., 1979; Johnson et al., 1979

Cetylpyridinium chloride E. coli

S. typhimurium 5.0-6.0 5.0-6.0 Cutter et al., 2000

Trisodium phosphate


0-4.3 0.1-0.3 0.1-2.9 0.5-4.1

Dorsa et al., 1998a; Dorsa et al., 1998b; Fratamico et al., 1996; Dickson et al., 1994; Delmore et al., 2000; Kim & Slavik, 1994; Dorsa et al., 1997

Cold water

APC E. coli Coliforms S. typhimurium

0.1-1.2 0.3-1.0

1.1 0.3-0.9

Anderson et al., 1979; Kang et al., 2001b; Dorsa et al., 1998a

Hot water APC E. coli S. typhimurium

1.5-2.2 1.3-2.7 2.5-2.2

Anderson et al., 1979; Dorsa et al., 1998a

Steam APC 0.1 Anderson et al., 1979

Low intensity Ultrasound APC 0.2 Pohlman et al., 1997

Multiple interventions E. coli Coliforms APC

1.3-2.2 1.2-2.2 1.0-2.5

Kang et al., 2001a; Kang et al., 2001b; Kondaih et al., 1985

Beef trim then ground beef

Hot water/cold water

E. coli Coliforms S. typhimurium APC

0-2.4 0.1

0-2.0 0.1-1.1

Stivarius et al., 2002a; Ellebracht et al., 1999; Dorsa et al., 1998a

Lactic acid


0.1-2.9 0.7

0.2-3.2 0-0.6

Stivarius et al., 2002a; Conner et al., 1977; Dorsa et al., 1998a

Acetic acid


0.1-2.8 1.3

1.5-2.8 0.1-1.3

Stivarius et al., 2002b; Conner et al., 1977; Dorsa et al., 1998a


Table 1 (continued). Selected postharvest interventions for beef tissue, cuts or in ground beef.

Antimicrobial Microorganism Inhibition (logs) Reference

Gluconic acid


0.3 0.2 0.1 0.5

Stivarius et al., 2002b

Trisodium citrate


0.1 0.1 0.2 0.2

Stivarius et al., 2002b

Chlorine dioxide


0.7 0.6 0.6 0.7

Stivarius et al., 2002c

Ozone

E .coli Coliforms S. typhimurium APC

0.1 0.2-0.4 0.5-0.8 0.3-0.6

Stivarius et al., 2002c

Trisodium phos-phate


0.8-2.3 0.7

0.7-3.1 0.6-0.7

Pohlman et al., 2002b; Dorsa et al., 1998a; Dorsa et al., 1998b;

Cetylpyridinium chloride


0.6 0.6 0.7 0.6

Pohlman et al., 2002b

Multiple inter-ventions


0.6-2.6 0.4-1.9 0.3-2.0 0.3-1.8

Pohlman et al., 2002a; Pohlman et al., 2002c;

Ground Beef - Direct

Sodium lactate E. coli APC

Delayed growth 0-0.8 Ajjarapu & Shelef, 1999; Harmayni et al., 1991; Maca et al., 1997; Eckert et al., 1997

Sodium diacetate E. coli

APC Delayed growth Delayed growth Ajjarapu & Shelef, 1999

Sodium acetate APC 0.1-0.6 Maca et al., 1997

Buffered cit-rate/Sodium citrate

APC 0-0.2 Maca et al., 1997

Potassium lactate Coliforms

APC 0.5-1.0 0.1-0.8 Egbert et al., 1992

Hydrostatic pressure E. coli ~2.2 Carballo et al., 1997

Multiple interventions evaluated are many including two or more combinations of heated mediums, organic acids, buffers, quaternary ammonia like mediums and oxidizers. “~” symbol means that reductions were approximated.


Table 2. Selected postharvest interventions for poultry, pork and lamb whole muscle or comminuted products.

Item Antimicrobial Parameter Microorganism Inhibition (logs) Reference

Chicken carcass Acidified sodium chlorite and citric acid spray

1,100 ppm sodium chlorite 9,000 ppm citric acid

E. coli Salmonella ssp. Campylobacter spp.

2.3 2.0 2.6

Kemp et al., 2001

Chicken carcass H2O prewash- (PR)

Acidifed Sodium Chlorite- ASC (A) Phosphoric (P) or Citric (C) acti-vated Dip or spray

500-1,200 ppm ASC E. coli Coliforms Aerobic

Phos. activated E coli- .72 Coliforms 1.51 Aerob- .72 Citric activated E coli ~ 2.3 Coliform ~.8-2.0 Aerob ~ .7-1.0

Kemp et al., 2000

Chicken carcass

Trisodium phos. (TSP) Lactic acid (L) Cetlypyridinium chloride (CPC) Sodium Bisulfate (SB)

TSP-10% L- 2.0% CPC- 0.5% SB- 5.0% spray

Salmonella typhi-murium Aerobes

TSP- .74-4.87 L-1.03- 1.77 CPC- 0.9-2.3 SB- 1.66

Yang and Slavik, 1998, Lillard, 1994, Wang et al., 1997; Breen et al., 1997; Xiong et al., 1998; Kim and Slavik, 1996

Chicken wings Lactic acid Sodium benzoate Wash (dip)

0.5% lactic 0.05% sodium benzo-ate

Salmonella ssp. Campylobacter spp. L. monocytogenes S. aureus E. coli

2.5 1.0 0.5 1.5 1.25

Hwang and Beuchat, 1995

Ground chicken Hydrostatic pressure 0-700MPa

Listeria Salmonella E. coli S. aureus

Up to ~ 1.7-7.5 Up to ~ 2.0 Up to ~ 5.7-6.0 Up to ~ 5-6

Patterson et al., 1995, Patterson et al., 1998, Yuste et al., 1999

Meat models Hydrostatic pressure 500MPa E. Coli, Staph spp., Listeria

1.3-5.54 Hugas et al., 2002

Turkey Breast, core 10 days

Sodium lactate (SL) Sodium diacetate (SD)

SL- 2.0% SD- .1% SL+SD- 2.0%+.1%

Clostridium spp. SL- 0.2 SD- .85 SL+SD- 0.8

Kalinowski and Tomkin, 1999

Ground turkey from RTE turkey breast

Sodium diacetate (D) Sodium nitrate (N) Sodium lactate (L) Pediocin (P)

D = 0.5, 1.0, 3.0% N = 30 ppm L = 2.5% P = 5000 AU/ml

L. monocytogenes

N+0.5%D- 3.41 L+0.5%D- 4.9 0.5%D- 4.96 P+0.5%D- 6.62

Schlyter et al., 1993

Pork Rib and Loin Chops

Acetic acid (A) Proprionic acid (P) Hypochlorite (H)

1.36M A+P 250 ppm H H+1ppb acetic acid sprays

Mesophilic bacteria A+P - 0-1.0 H- 0- 0.1 H+A- 0.2-0.5

Carpenter et al., 1986

Pork Chops Acetic acid- (A) Lactic acid- (L), dip

1% A 1% A+1.0% L

Lactobacillus Enterobacters

.1-.25 1.0-2.5 Mendonca et al., 1989

Pork Loins Acetic acid Lactic acid Citric acid

1.5% A 1.5% L 1.5% C

Coliforms APC E. coli

A- 2.5, L- 0.5 A- 1.25, L- 0.0 A- 0.5, L- 0.1

Fu et al., 1994

Pork trim meat Cores (dip)

Lactic acid Hot water Hot air

Water + 2% L (WL) Water, HA, + L- (WHL)

Aerobic Coliforms E. coli

WL- 3.0, WHL- 2.0 WL- 2.25,WHL- 2.2 WL- 2.0, WHL- 2.0

Castelo et al., 2001

Lamb Carcass Muscle cores Acetic acid 1.5 or 3.0%, Dip or

Spray

B. thermosphaeta Aerobic Coliform

B.T. - 2.5 log 3% dip No other trt effects Anderson et al., 1988

Sheep Subcuta-neous Hot water Spray Salmonella spp.

E. coli 4.0 log 4.0 log Smith andGraham, 1978


For pork, a number of postharvest decontamination stud-ies have been performed on various pork loin chops. Using acetic acid on pork loin chops, reductions in various bacte-rial populations have been reported from 0-2.5 logs (Car-penter et al., 1986; Mendonca et al., 1989 and Fu et al., 1994). Reductions in microorganisms on pork loin chops have also been reported for 0-2.5 logs with lactic acid used singly or in combination with acetic acid (Mendonca et al., 1989 and Fu et al., 1994). In other work, Castelo et al. (2001) was able to reduce APC, coliforms and E. coli by 3.0, 2.3 and 2.0 logs, respectively on pork meat trim using water and a 2% lactic acid treatment.

Although much limited in the body of research on lamb postharvest interventions, a few studies have been con-ducted. While Anderson et al. (1988) was able to reduce B. thermosphaeta on lamb muscle cores by 2.5 logs using a 3.0% acetic acid dip, they reported no reductions in APC or coliforms with acetic acid treatment. However, Smith and Graham (1978) reported 4.0 log reductions of both Salmo-nella spp. and E. coli on sheep subcutaneous tissue using hot water.

While the technologies discussed previously represent a cross-section of intervention technologies that have been researched, there are still a number of additional technolo-gies with antimicrobial properties for reducing microbial loads on or within meat products. Examples of these might be hydrogen peroxide, pulsed light, copper sulfate pentahy-drate, ultraviolet light, x-rays and irradiation to name a few. While a number of these technologies might hold promise for postharvest pathogen reductions and interventions, be-cause of the infancy of postharvest research, the regulatory status for use of a number of these technologies has not caught up to the science. While a number of these tech-nologies have been approved for carcass decontamination applications, less have been approved for postharvest pathogen reduction. While some interventions have been approved and commercialized for use such as the use of ozone, a chlorous acid system and a peroxyacid system, others await regulatory approval. In addition to approval and microbial reduction effectiveness, other issues for tech-nology adoptions include the impact of postharvest patho-gen reduction technologies on processing characteristics, color, shelf-life and sensory characteristics. While occa-sionally research has addressed these concerns, the largest body of information remains on antimicrobial effectiveness alone. Therefore, as more interventions are approved for postharvest applications, additional research will be neces-sary to answer processing and quality issues.

Conclusions While substantial research has been conducted using an-

timicrobials for carcass decontamination, it is only more recently that research has begun to focus upon postharvest pathogen reduction. Although intervention technologies have led to declines in microbial loads on carcass surfaces, since these technologies do not render the carcass sterile,

processing contamination of cut surfaces can occur when carcasses are fabricated due to contamination through meat contact with knives, conveyors, human hands etc. There-fore, the use of postharvest interventions may offer an addi-tional pathogen reduction that might benefit the consumer directly in the package. Additionally, since ground beef can be of special concern with regard to meat safety, the use of these intervention technologies might also hold promise for reducing microorganisms and pathogens in this product. However, using the multiple intervention approach, the greatest benefits might be achieved with concerted inter-vention strategies at several steps through the processing chain.

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static pressure and mild heat on inactivation of pathogens in milk and poultry. Journal of Food Protection 61: 432-436.

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M.G. 2002c. Reduction of microorganisms in ground beef using multi-ple intervention technology. Meat Science 61:315-322. Xiong, H.; Li, Y.; Slavik, M.F.; Walker, J.T. 1998. Spraying chicken skin

with selected chemicals to reduce attached Salmonella typhimurium. Journal of Food Protection 61:272-275. Schlyter, J.H.; Glass, K.A.; Loeffelholz, J.; Degan, A.J.; Luchansky, J.B.

1993. The effects of diacetate with nitrite, lactate, or pediocin on the viability of Listeria monocytogenes in turkey slurries. International Jour-nal of Food Microbiology 19:271-281.

Yang, Z.; Li, Y.; Slavik, M. 1998. Use of antimicrobial spray applied with an inside-outside birdwasher to reduce bacterial contamination on pre-chilled chicken carcasses. Journal of Food Protection 61:829-832.

Smith, M.G.; Graham, A. 1978. Destruction of Escherichia coli and Salmo-nellae on mutton carcasses by treatment with hot water. Meat Science 2:119-128.

Stivarius, M.R.; Pohlman, F.W.; McElyea, K.S.; Waldroup, A.L.. 2002a. Effects of hot water and lactic acid treatment of beef trimmings prior to grinding on microbial, instrumental color and sensory properties of ground beef during display. Meat Science 60(4):327-334.

Stivarius, M.R.; Pohlman, F.W.; McElyea, K.S.; Apple, J.K. 2002b. The effects of acetic acid, gluconic acid and trisodium citrate treatment of beef trimmings on microbial, color and odor characteristics of ground beef through simulated retail display. Meat Science 60(3):245-252.

Yuste, J.; Mor-mur, M.; Capellas, M.; Guamis, B.; Pla, R. 1999. Listeria innocua and aerobic mesophiles during chill storage of inoculated me-chanically recovered poultry meat treated with high hydrostatic pres-sure. Meat Science 53:251-258.


R E C I P R O C A T I O N S E S S I O N

Livestock and Poultry Care and Welfare

Janice C. Swanson

Introduction Attempts to regulate on-farm care of livestock and poultry

have, for the most part, been unsuccessful at the federal level. However, states are the new staging grounds for set-ting public policy and practices for farm animal care. The most notable event was the passage of the Florida referen-dum banning sow gestation stalls. Couple this with the re-cent actions by food retailers and you have an industry un-der siege. Is this the clarion call for setting national stan-dards for the care of livestock and poultry? Is the public concerned about the conditions and practices to which our livestock and poultry are subjected?

A carefully planned, expertly worded, third party survey into the values and attitudes of the public relative to the care and treatment of farm animals would be enormously useful to plotting the course for industry. However, many surveys fall short of this goal. For example, an industry commissioned survey of consumers (defined as an individ-ual who eats their product) is conducted at randomly se-lected grocery sites. The survey reveals that consumers of the product do not rank animal welfare at the top of their list of concerns. Does this mean industry is not obligated to change except when a specific consumer public com-mands? Are product consumers the only stakeholders in the welfare of the animal? History tells us that a more democ-ratic process has been used to determine outcome of animal treatment issues (Garner, 1998). Be it through state referen-dum or federal legislation or social mandate. Therefore the process by which action is taken (public at large) should also be reflected in the process by which concerns are as-sessed. Current survey work may fall short of inclusiveness, but does reveal that the nature of the questions posed con-centrate on factors that can be collectively described as “quality of life.”

Quality of Life What makes up the quality of life of animals and birds

under our care? We can start by recognizing that each spe-cies has been shaped by years of natural and artificial selec-tion. Specialized beaks or muzzles, two or four legs, wings, digestive differences, breeding differences, and the list goes on. In some instances artificial selection has not sought to change a fundamental need, for example, social behavior. Our domestic livestock and poultry evolved from ancestors with a strong (and naturally reinforced) behavior to live in social groups. This behavior was also conducive to domes-tication and successful exploitation in agriculture. Fitness and survival were greatly enhanced by the successful exe-cution of social behavior thus this trait remains solidly em-bedded within the framework of farm species. For example, sheep display an extreme stress response to social isolation and restraint that can affect meat quality (Apple et al., 1995). Therefore the quality of life of many of our domestic agricultural species includes social interaction or contact. Although undesirable social behavior has been manipulated (e.g. temperament, feather pecking) there has been no con-centrated effort to eliminate sociality as a whole. Other fac-tors such as lack of fear, avoidance of unnecessary pain and distress, and ability to adapt and perform a reasonable range of normal behavior under production conditions con-tribute to the quality of life an animal will experience.

In addition to behavior, known physiological demands such as food, water, shelter, bedding, temperature, preven-tive health measures, control of indoor environments and atmospheric quality, etc. round out the picture. The more restrictive and contained an environment becomes the greater the number of variables we control (versus the ani-mal) for the quality of life. Quality of life can be impinged or certain aspects sacrificed as economic conditions dictate – another two hens in the cage, pigs in the pen, or cattle in the lot. Striking a balance between the quality of life de-mands by stakeholders is the challenge.

Science and Values Perhaps the most troublesome aspect of livestock and

poultry care is setting a baseline for the quality of life. A cheap, abundant and safe food supply has been one of the guiding principles in agricultural production. Agricultural researchers use scientific methods to elucidate how to best reach the goal of producing an affordable, abundant and

Janice C. Swanson Kansas State University, Manhattan 129 Weber Hall Manhattan, KS 66506-0201 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 49-50) June 15-18, 2003, Columbia, Missouri www.meatscience.org


safe food supply. Thus, science is driven by values, whether it is to value human life by curing disease or to discover efficient ways to raise animals for food. However, values can and do differ within a culture (public, corporate, scien-tific, etc.) . Variables selected to assess quality of life for a species can be influenced by these values (Fraser, 1999; Rollins, 1995; Thompson, 1993). For example, space allot-ment is a highly debated issue. Even the unsophisticated can conceptualize the value of space and related freedom of movement. But, animal and poultry scientists may seek to minimize space, maximize productivity and capture new efficiencies to satisfy a competing set of values. So the base-line for quality of life will differ depending on which set of values become operational. This also explains the differ-ences in animal care standards acceptable to members of the European Union versus the United States. Operating values should be weighed into the development and as-sessment of animal care when setting the baseline for qual-ity of life.

International Standards Food retailer activity in the arena of livestock/poultry

care and welfare indicate their concern with providing as-surance to their customers. The clout of the American pub-lic appears to be arriving by way of social pressure rather than traditional politics (Schweikhardt and Browne, 2001). In an intensely competitive industry such as the grocery and quick serve restaurant, sensitivities run high to customer concerns. After all, they hand the product directly to the consumer.

Considering the global nature of the food retail business, and the legislative actions by westernized countries, will international standards for animal welfare emerge? The World Organization for Animal Health, also known as the Office of International Epizooties (OIE), established an Ani-mal Welfare Working Group in October 2002 (OIE, 2002). The mandate of the working group is to address public de-mand for animal welfare, to develop knowledge on the sub-ject, propose recommendations at the international level and to integrate ethical, scientific, economic and political dimensions of the issue to achieve balance in decision mak-ing. Since animal welfare is not specifically addressed un-

der the World Trade Organization’s Sanitary and Phytosani-tary Agreement, member countries of the OIE requested guidelines and recommendations establishing best animal management practices that are congruent with good animal welfare. The OIE has identified priority issues for animals used in agriculture and aquaculture as follows: transporta-tion, slaughter, killing for disease control, housing, and management practice. Members of the working group have been appointed from Canada, New Zealand, Belgium (EU), Kenya, India and Egypt. At the time of this writing there are no members from the United States appointed to the pri-mary working group. The development of this international working group, coupled with the announcements of food retailers such a McDonalds Global Animal Welfare Stan-dards (McDonalds, 2002), signal a social and political im-petus to coordinate and address the issue.

References Apple, J.K.; Dikeman, M.E.; Minton, J.E.; McMurphy, R.M.; Fedde, M.R.;

Leith, D.E.; Unruh, J.A. 1995. Effects of restraint and isolation stress and epidural blockade on endocrine and blood metabolite status, muscle glycogen metabolism, and incidence of dark cutting longissimus dorsi muscle of sheep. Journal of Animal Science 73:2295-2307.

Fraser, D. 1999. Animal ethics and animal welfare science: Bridging the two cultures. Applied Animal Behaviour Science 65:171-189.

Garner, R. Political Animals: Animal Protection Politics in Britain and the United States. The Ipswich Book Company, Ipswich. 1998.

McDonald’s Corporation. 2002. McDonalds Corporate Social Responsibil-ity: Global Animal Welfare Progress Report: 2002. http://www.mcdonalds.com/corporate/social/marketplace/welfare/update/index.html

Office of International Epizooties. 2002. The OIE Initiatives in Animal Welfare. http://www.oie.int/eng/bien_etre/en_introduction.htm

Rollin, B. E. Farm Animal Welfare: Social Bioethical, and Research Issues. Iowa State University Press, Ames. 1998.

Schweikhardt, D. B.; Browne, W. P. 2001. Politics by other means: The emergence of a new politics of food in the United States. Review of Ag-ricultural Economics 23:302-318.

Thompson, P. B. 2001. Animal welfare and livestock production in the postindustrial milieu. Journal of Applied Animal Welfare Science 4:191-205.



Pork Muscle Profiling

Dennis R. Buege*, Joe Sebranek, Matt Doumit, Dennis Marple, Dong Ahn, Elisabeth Huff-Lonergan, Steve Lonergan, Chris Fedler, Ken Prusa, Emily Helman, David Meisinger

The shoulder and ham primals of pork carcasses have traditionally been marketed to processors and retailers in intact form, for fabrication and manufacture into consumer products containing the variety of muscles found in those cuts. In recent years, the meat processing industry has sought to develop new value-added products by discover-ing unique properties of single muscles or groups of mus-cles from primal cuts. To facilitate this effort, it is very im-portant to understand the characteristics of individual mus-cles. The objective of this project was to determine the physical and chemical properties of significant muscles from the ham and shoulder, to enhance selection of raw materials from these primals to use in developing new value-added pork items.

Methods This research was cooperatively conducted by scientists

and technical staff from Iowa State University, Michigan State University and the University of Wisconsin. The work was financially supported by the National Pork Board.

Pork carcasses were selected from a single packer, which purchases pigs on the open market from a variety of pro-ducers employing a wide range of genetic lines. Carcass selection followed pre-determined guidelines for specific carcass weight ranges, estimated carcass percent muscle and pH at 45 minutes postmortem (an indicator of lean quality), to assure an appropriate distribution of carcasses varying in these criteria. After 24 hours of chilling, carcasses were transported to the Meat Science Laboratory at Iowa State University.

Between 48 and 80 hours postmortem hams and shoul-ders from both sides of selected carcasses were fabricated into individual muscles. Muscles of significant size (0.5 pounds or larger) were evaluated for the following proper-

ties: weight, physical dimensions, pH, sensory properties, objective tenderness, objective color, water-holding capac-ity, protein solubility, gel strength, pigment concentration, total collagen and nutrient content.

Results The results from the chemical, physical and nutritional

evaluation of 25 significant shoulder and ham muscles have been organized into a multi-level classification system for each parameter measured. For example, the mean pH value of each muscle is classified as low, medium or high pH, and the mean sensory tenderness of muscles is described according to a five descriptor scale, encompassing very tender, moderately tender, average tenderness, moderately tough and very tough. With such descriptions defined for all muscle parameters evaluated, a determination can be con-sidered for the most appropriate potential use of individual muscles or closely-adjacent muscle groups. A section of longissimus muscle from each carcass (from the fifth rib forward) was included in these evaluations, to serve as a familiar benchmark. As an example of the output generated from this work, Table 1 presents the results of the evalua-tions and analyses performed on the Semitendinosus and Longissimus dorsi.

Representatives from the pork processing industry will review and react to these findings on the characteristics of individual muscles, and provide input into their merchan-dising potential. Not only are the size, shape and character-istics of individual muscles important to their potential ap-plication, but also the accessibility of the muscles and their ease of removal from the shoulder and ham primals, using current and possible future fabrication methods, will be critical factors in determining muscle use.

The desired outcome of this comprehensive determina-tion of the properties of the individual ham and shoulder muscles is to identify those muscles which possess appro-priate characteristics and realistic fabrication potential, to be able to be merchandised as higher-value products. Such an outcome would increase the overall value of these pri-mals to the processing industry, and ultimately add value to the total pork carcass, to the benefit of pork producers and pork processors.

D. R. Buege Muscle Biology and Meat Science Laboratory University of Wisconsin 1805 Linden Drive Madison, WI 53706 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 51-52) June 15-18, 2003, Columbia, Missouri www.meatscience.org


Acknowledgments Iowa State University

Aaron Asmus Jerry Knight Matt Gardner Terry Houser Travis Krause Elaine Larson Graciela Mendez

Byongrok Min Kwangsoon Park Randy Petershon Matt VanUtrecht Haijie Yan Jacob Yates Amy Yelden

Michigan State University Charles Allison Nick Berry Courtney Dilley Sarah Erickson Brigitte Grobbel Matt Ritter Stacy Scramlin

University of Wisconsin Elizabeth Dobbs Wayne Ellefson Laura Trumble

Table 1. A comparison of the chemical and physical properties of raw pork Semitendinosus and longissimus dorsi.

Semitendinosus Longissimus dorsi Weight (lbs). 1.23 1.53

pH Classification mean value

average (6.12)

low (5.81)

Water-Holding Capacity mean value (%)

low (91.77)

low (92.29)

Color mean L* mean a* mean b*

average (48.3) (20.1) (6.1)

light (53.0) (17.5) (5.3)

Color Uniformity two-toned uniform

Fat Content mean fat (g/100

average (5.7)

average (3.2)

Total Iron mean iron (mg/100 g)

(0.98)

(0.78)

Heme Pigment mean value (mg/g)

(0.99)

(0.82)

Collagen mean value (mg/g)

(6.53)

(3.96)

Protein Solubility high high

Overall Tenderness mean sensory mean star probe

average (102/150)

(4.18)

moderately tender (104/150)

(4.49)

Texture fine-textured average

Flavor moderate pork flavor light meat pork flavor

Recommended Category fresh-- enhanced fresh -- enhanced

Product Suggestions medallions, roast chops, roast



Cow Muscle Profiling

Chris R. Calkins, D. Dwain Johnson and Bucky L. Gwartney

Building on the success of the muscle profiling research, the University of Nebraska and the University of Florida undertook to profile the characteristics of muscles from beef and dairy cows. The National Cow and Bull Audit con-ducted by Colorado State University estimated that 43% of the market cow carcass is sold into boxed beef form. While this number is higher than many may have guessed, oppor-tunities still exist to upgrade the value of cow muscles. This research was conducted to characterize 21 muscles in mar-ket cows, to compare dairy and beef cow muscle character-istics, and to explore the effects of carcass weight, maturity, muscling and fat thickness on these traits.

Over a 5-month period, 75 beef and 74 dairy carcasses were selected from 4 different plants to fit a grid of carcass weight (350 to 549 and 550 to 749 lb for beef and 550 to 749 and 750 to 949 lbs for dairy), fat thickness (0.1 inches of fat or less, or greater than 0.1 inch), muscling (light ver-sus medium/heavy), and C/D or E maturity groups. A por-tion of the carcasses went to the University of Florida for shear force determination and taste panel evaluation and a portion went to the University of Nebraska for analysis of composition, color, heme iron, collagen content, pH, and water holding capacity. During fabrication, measures of muscle dimension and yield were also obtained.

One difference between this study and the A-maturity muscle profiling project is the muscles that were studied. Earlier, we focused on muscles of the chuck and round. In

this study, we examined muscles from all of the major pri-mals, using size and weight as the primary selection crite-rion. We examined the following muscles: adductor, biceps femoris, complexus, deep pectoral, gluteus medius, in-fraspinatus, latissimus dorsi, longissimus dorsi, multifi-dus/spinalis dorsi, psoas major, rectus femoris, semimem-branosus, semitendinosus, serratus ventralis, supraspinatus, tensor facia latae, teres major, triceps brachii, vastus inter-medius, vastus lateralis, and vastus medialis.

As expected, there was a fair amount of variation among the muscles for most of the traits considered. There were few significant effects of carcass weight, maturity, muscling and fat thickness on the muscle characteristics on a within-breed type basis. Generally, there were few differences in muscle traits between the beef and dairy cow populations. When comparisons were made, we compared only those carcasses that were similar in weight (i.e., the heavy weight beef cow carcasses were in the same weight range as the light weight dairy cow carcasses). Dairy cows tended to be a bit more consistent in most traits.

This database will provide the foundation for product en-hancement and value-added initiatives for cow muscle. It will be included in a revised version of the bovine myology CD-ROM.

C. R. Calkins Professor of Animal Sciences University of Nebraska - Lincoln A213 Animal Science 38th and Fair Street, Box 830908 Lincoln, NE 68583-0908 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (p. 53) June 15-18, 2003, Columbia, Missouri www.meatscience.org



Beef Muscle Profiling Research

D.D. Johnson*, K.H. Johnson*, C.R. Calkins, B.L. Gwartney

Situation When beef demand declined by more than 20 percent

from 1980 to 1998, a research initiative was sparked to produce leaner and more convenient beef products. As marketing experts evaluated the decline in greater detail, it was noted that the decline in demand for beef was not equally distributed across all portions of the carcass. When consumer demand (adjusted for inflation) was evaluated by wholesale cut, it was found that the rib and loin, also called the “middle meats”, were up in value by 3-4 percent from 1993 to 1998. In contrast, the chuck, round and “thin cuts”, which make up 73 percent of the beef carcass weight, had declined by more than 20- 25 percent in value during this same time period. Therefore, the Cattlemen’s Beef Board realized that a more concentrated effort was needed to study the cause for the decreased demand in these prod-ucts. Moreover, they aimed at finding out what could be done to reverse the trend and increase the demand for the chuck and round cuts.

To address this issue, hurdles were identified as a means to gain ground on demand and value of the chuck and round. The chuck and round are the locomotive portions of the animal; these areas are less tender than the muscles of support from the rib and loin. Also, they are more variable in tenderness. There are exceptions to this situation because some muscles in these carcass areas are very tender, which has been known for many years. Another identified hurdle is the internal and external connective tissues present within the muscles of locomotion. In these areas, intermuscular or seam fat can be present, which is very objectionable to the consumer. As a result of the above-listed hurdles (i.e. less tender muscles and greater amounts of connective tissue), consumers have always had to use a long-time, low-temperature cooking method, which was not convenient for today’s consumer. Using this method to cook meat would take several hours rather than 30 minutes or less as most

people desire. As a means to attack the demand slide, espe-cially in the chuck and round portion of the carcass, the National Cattlemen’s Beef Association under direction from the Beef Board, called for research to address these hurdles in 1998.

Rationale The research requested by the National Cattlemen’s Beef

Association was to fill the gap in knowledge about the lesser known individual muscles in the chuck and round. This request included profiling each muscle for palatability characteristics, composition analysis, yields, physical char-acterizations, and included how the muscle traits were af-fected by factors such as USDA Quality, Yield Grade and hot carcass weight. It became readily apparent that this was a massive request that would require cooperative work to accomplish in a timely manner. The research work was conducted by the Department of Animal Sciences at the University of Florida (UF) and the Animal Science Depart-ment at the University of Nebraska. The study was called “Muscle Profiling”. The UF Department of Animal Sciences contributed to the study by measuring objective tenderness and by conducting sensory panel evaluations for each of the muscles. In addition, UF characterized the yields and physical characteristics of each muscle. The University of Nebraska contributed to the study by performing color analysis, muscle fiber typing, composition (moisture, fat, ash), connective tissue concentration, pH, heme iron, ex-pressible moisture and emulsion capacity. Together, the universities evaluated more than 5,600 muscles during a two-year period. The culmination of that work was the pro-duction of a monograph by NCBA entitled “Muscle Profil-ing”. The production of the 100-page document serves as an “encyclopedia” of information for meat packers, proces-sors and purveyors. The monograph has been translated into five different languages and has been utilized to de-velop new and more convenient, leaner, yet more palatable products for consumer marketing. Also, the information gleaned from the Muscle Profiling work was combined with other data, and a Web site was created. The Web site, Bo-vine Myology, is currently maintained by the University of Nebraska Meat Science section within their animal science department. Bovine Myology can be found on the Internet at http://deal.unl.edu/bovine. This Web site serves as a tool for the industry and as an educational medium for various audiences including university meat science and muscle biology groups. The Web site is constantly updated with

D.D. Johnson PO Box 110910 Department of Animal Sciences University of Florida Gainesville, FL 32611-0910 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 55-56) June 15-18, 2003, Columbia, Missouri www.meatscience.org


new data, additional research as it is reported, and innova-tive methods of data delivery.

The Muscle Profiling work revealed gaps in knowledge that have been filled by other institutions and the Meat Sci-ence group at the University of Florida. In the University of Florida study, muscles of marginal palatability were identi-fied and subsequently enhanced by post-harvest marination technology to determine what improvements could be pro-duced. It was noted in that study that all muscles do not respond to post-harvest enhancement to the same degree. However, four out of eight muscles did show improvement in tenderness of more than 15 percent. Another study con-ducted by the Meat Science group at the University of Flor-ida evaluated the postmortem effects of aging on the ten-derness development in muscles of the chuck and round. Work has been reported on the beneficial effects of post-mortem aging on meat tenderness, but these studies have primarily concentrated on the wholesale rib and loin. The University of Florida study found that the chuck and round muscles responded in a similar way to postmortem aging effects, and it was determined that there was an effect of the intramuscular fat on tenderness development in these mus-cles as well. The muscles with higher intramuscular fat would need fewer days of postmortem aging than would muscles of lower intramuscular fat. Other studies have been conducted as an offshoot of the Muscle Profiling work and are being reported at this meeting as well at other research and industry meetings.

Impact Numerous groups have used the Muscle Profiling re-

search to find new ways to fabricate, process and prepare meat from the chuck and round. One of the most significant

efforts has been from the R & D Ranch group of the Na-tional Cattlemen’s Beef Association. This group is the prod-uct development arm of the National Cattlemen’s Beef As-sociation, and it is responsible for promoting new product development within the beef industry. Instead of merchan-dising the chuck and round as less convenient multi-muscle cuts, the R & D Ranch group used the Muscle Profiling data (which suggested new cuts and merchandising methods) to market cuts in a singular fashion. The new cuts decreased the length in cooking time and appealed to consumers. The R & D Ranch group coined the term “Beef Value Cuts”, and they have produced cutting brochures, manuals and instruc-tional videos on removal and merchandising. A Web site offering technical support is also available at www.rdranch.com. The R & D Ranch group has followed up with regional training seminars for processors, distribu-tions, food service groups and retailers. In addition, they match these efforts with a publicity campaign in conjunc-tion with food-service-trade advertising. Many other groups within the beef retail business have incorporated these ideas into marketing new items from the chuck and round which have not been previously available to the consuming pub-lic. Other segments of the beef industry have developed new products based on findings from the Muscle Profiling work, and they are currently featuring these new products on the market. Moreover, the U.S. Meat Export Federation has identified several applications from the Muscle Profiling work that are being incorporated into their efforts to export more high-quality beef to markets outside the United States. Recent data from Cattle Fax, a firm that monitors market trends, indicates an increase of 10 percent in total beef de-mand from 1998 to the last quarter in 2002. This increase is indeed encouraging and suggests a reversal in the slide for beef demand in these lower value portions of the carcass.



Soy Protein Ingredient Technology

Larry W. Hand

Soy proteins have come a long way from the early products of the 60’s and 70’s, or even the 90’s. The changes made in flavor and functional technology have been revolutionary. These changes provide soy protein products that are valuable tools in the toolbox of the product developer, when they are faced with developing new innovative items or redesigning those items they already manufacture. In order to be success-ful, a product developer must be aware of the consumer re-sponse to soy proteins, as well as, the forms and functional properties of the different soy protein products.

Although meat industry traditionalists have long been nega-tive in regards to inclusion of soy protein as an ingredient, con-sumers have a much different outlook in regards to the foods that they purchase. In a consumer attitude study (Prima Market-ing Group, 1996), it was found 82.5% of consumers have no issue with a food manufacturer using soy protein in their food and meat products. In the same study 56% of consumers ex-pected no taste difference and 27% expected better taste in products containing isolated soy protein. Since the FDA ap-proved a health claim for foods containing at least 6.25 g soy protein per serving (Federal Register 1999), the interest in soy protein as an ingredient in meat products has increased. With this interest in soy protein, the meat product developer needs to be aware of the functional properties of soy protein that can impact their products.

With the myriad of soy protein products available and their different functional attributes, the selection of the appropriate soy protein is critical to product success. Soy protein comes in three basic categories, soy flours (50% protein), soy concen-trates (70% protein) and soy isolates (90% protein). These all can come in different forms such as powdered, textured, and colored. The functional properties of soy proteins impact their performance in a meat system. Some of the properties of con-cern are water and fat stabilization, solubility, viscosity, gela-tion, emulsification, flavor and texture. Because of their func-tional properties, we can achieve economic benefits, product

improvement or product differentiation through their use.

Soy proteins have unique attributes that allow them to com-plement meat proteins in meat products. Soy proteins are more hydrophobic than meat, have thermoreversible gels, retain water when heated, and when denatured can be highly soluble and functional. In comparison to meat trimmings, soy proteins are much less variable as they are manufactured to specific tolerances. Soy protein inclusion can improve eating qualities by making the meat products juicier, firmer, and more tender. The moisture retention properties of soy proteins allow better performance upon reheating, especially upon microwave re-heating. Cost reduction through soy protein inclusion occurs by replacement of lean meats, the utilization of lower value cuts or trimmings and the reduction of certain processing steps. These functional properties can impact finished product per-formance - through increased cook yields, better slicing yields and reduced package purge. The use of soy proteins can also have dramatic effects on texture. Soy protein can be developed to have almost any texture that you desire. Therefore, one can manipulate the texture of a meat product in a myriad of ways – from making something loose and crumbly to very tightly bound.

Understanding the characteristics of the soy protein of choice is important, but the selection is predicated on good project definition. An understanding of the business objectives and strategies of the company is important to position the new or improved product. Before a project begins, the technical objectives need to be defined, with constraints identified. As there is no “magic” ingredient that solves all issues and con-straints, the knowledge of the benefits and liabilities of all in-gredients available is critical to developing a solution to the project objectives. Only after these are well understood can the product developer develop the appropriate solution and select the correct soy protein or proteins for the project at hand. This way the project will successfully meet the identified product and project specifications.

References Federal Register, 1999. Food Labeling: Health Claims; Soy Protein and

Coronary Heart Disease, Code of Federal Regulations 21, Part 101, Food and Drug Administration, Washington, D.C., vol 64, nr 206, 57699-733.

Prima Marketing Group, Inc. 1996. Food Ingredient Survey. Elk Grove Village, IL.

L.W. Hand The Solae Company P.O. Box 88940 St. Louis, MO 63188 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (p. 57) June 15-18, 2003, Columbia, Missouri www.meatscience.org



Computer Assisted Meat Science Education

Steven J. Jones, Vishal Singh, and Brad Franklin

Introduction As instructors, we are always trying to find new ways to

present information in a clear and concise manner that stu-dents will be able to grasp and retain. There have been many changes since the time that instructors used the chalkboard and lecture format. Today with the use of com-puters it is possible to bring into the classroom multimedia presentations to liven up instruction and improve student learning. The computer has also redefined the classroom, allowing instruction to be shared in different locations via the internet. Today, most of the classrooms have equip-ment, which makes it possible to use a computer in class-room. Most households have a computer that is generally connected to the internet. Today’s students are very com-puter literate and have used computers for instruction since they began their formal education.

As instructors in Meat Science, we can utilize this tool to improve our instruction and expand our influence to more students. Before one can fully utilize computers in Meat Science instruction the why, what, how, and who questions must be answered. Hopefully, this presentation will answer some of these questions and stimulate some interest in in-corporating the computer in Meat Science education.

There are generally four areas to be considered to suc-cessfully use computers in instruction. They are:

1. Who is the audience the instructional material is in-tended for?

2. What is the content you would like to share with the student?

3. What medium will be used to present the material?

4. How will the information be organized for use by the student?

Audience When examining the audience there are several details

that must be considered to determine what multimedia tool can be used. The computer resources the student has avail-able must be taken into consideration. Computer speed, type of network connection, graphics and audio capability will determine what you can provide to the student. If the information is going to be used for resident instruction, most students will have access to a high-speed connection. This will make it possible to share video and other media, which requires a large bandwidth. If students are using a modem connection and there is video information you would like to share, it can be copied to a CD and distributed. The best way to present the information is in a web format because most computers will have a web browser that can be used. This will make it possible to share information over the web, but it can also be read from a CD with the purchase of propriety read software. Also, be aware not all web brows-ers are created equal. An application that works on Micro-soft Internet Explorer may not function properly on Net-scape Navigator, this may also be true with the version of the browser that is in use. If the information is going to be shared on a CD, be sure it has been tested on many operat-ing systems and computer platforms to assure proper opera-tion.

Content This presentation will not deal much with the actual con-

tent. Every instructor knows what he or she would like to have the students in their course learn. Other factors you must consider are your teaching philosophy, your expecta-tion for the students, your teaching models, and tools and resources at your disposal. These factors will all affect your use of the computer in the classroom.

To be successful in creating computer teaching aids it is necessary to divide information into concepts or principles. For example, to demonstrate thaw rigor, one may want to take time lapse pictures of a muscle frozen pre-rigor then thawed. Another example may be use of animation to de-scribe the process of contraction. The more the concept is defined the easier it will be to develop a computerized presentation. It will also help to identify the medium that can be used to demonstrate the concept. Remember, devel-oping computerized instruction material is an evolutionary process. Begin with specific concepts you want to show in your class then slowly add other computer-assisted presen-

S. J. Jones Professor University of Nebraska - Lincoln A213 Animal Science Complex Lincoln, NE 68583-0908 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 59-62) June 15-18, 2003, Columbia, Missouri www.meatscience.org


tations. Keep in mind what your learning objectives are and the direction you are going to take the course.

Presentation Medium As one goes through the process of selection of which

medium will be used to demonstrate a concept or principle, a key point to remember is to use the medium most suited to demonstrate the concept without going overboard. If we were to examine the resources, both time and computer resources, necessary to develop computer aided instruction concept, they could be listed from greatest to least as fol-lows: video, animation, audio, pictures, and finally, text. For example, if a single picture will show the point that needs to be made, do not go through the effort of develop-ing an animation or video. Not only is this time consuming in development, it will also require more bandwidth to transmit to the users.

The question is, what resources are required for each of the various types of medium. This presentation will focus on what is needed.

Text Providing text information is probably the easiest method

of putting information on a web site or in a computerized presentation. With the addition of HTML coding, text documents can be placed on the Internet. Most of the word processing programs have a save feature which will insert HTML coding. If one wants to be more sophisticated, there is software that will prepare documents for web publication quickly. The following is a list of popular web editing pro-grams:

• Dreamweaver (www.macromedia.com)

• Front Page (www.microsoft.com)

• Go Live (www.adobe.com)

• Pagespinner (www.optima-systems.com)

A second method of sharing text information is through a dynamic web site. With this method of presentation, infor-mation can be entered into a database separate from the actual website. The web page would then be programmed to access information from the database. An example of this is in the bovine myology and muscle profiling web site. The user is able to “click” on a muscle and fetch the relevant data in a format that is easy to read and interpret. As a desk-top or web-based application, this process can be accom-plished by constructing dynamic presentations that are con-structed “on-the-fly”. In this manner the content is separated from the design and a single routine or program can gener-ate an infinite number of different web pages (or screens) using content from a database. Dynamic sites are common, with news organizations providing some of the best exam-ples. Unfortunately, dynamic sites are driven by the web-server not the web browser. Such an application is possible to host on a web server, but not possible to run from a CD-ROM, unless the computer can run both a web server and database server.

If the information is going to be used in a classroom presentation, a Microsoft Power Point presentation may be the easiest method available. This has been used in many instances and in most situations, has replaced transparen-cies on the overhead projector. Power Point presentations can also be incorporated into a web page. Courseware pro-grams such as, Blackboard or Web CT will allow access of the presentations to the students. The student will need to have Power Point on their computers or a Power Point player. Since Power Point is a Microsoft product, it works best using Internet Explorer.

Another method of using a Power Point presentation is to save it as an HTML document. This will allow Power Point to be viewed through the browser. The disadvantage of this is it will be too large to be viewed adequately if the student is on a modem connection. One way to get around this is to save it as a flash animation, which will make it easier to access and reduces the file size.

Photo Images A picture is worth a thousand words and can really help

the student to understand a key concept. If there are plans to use photos in presentations and on a web site, then pur-chase of a digital camera is important. One can spend thou-sands of dollars on a camera, but in most cases it is not necessary. The high end mega-pixel camera is important if the pictures are intended for print copy, but in most cases the pictures taken with these cameras must be resized to effectively run in a web-based environment. Features that are useful are: high quality optics, ability for time lapse pho-tography, macro capabilities, use of outside lighting, large image storage capacity and camera recovery time. There are many other features that digital cameras have, which will assist in obtaining quality pictures.

Once the images have been obtained, they can be modi-fied using one of the many image software programs. These programs can perform functions from cropping to color ad-justment. Labels and other graphics can be added to the images to assist in describing the picture. Some of the pro-grams that are available are:

• Photoshop; Abode Inc (www.adobe.com)

• Photoshop Elements; a smaller version of Photoshop with most of the features

• Fireworks; Macromedia (www.macromedia.com)

• Paintshop Pro; Jasc Software (www.jasc.com)

• Corel Draw; Corel (www.corel.com)

The size of the picture you plan to use on the web is also important. If they are too large they will upload very slowly frustrating those using a modem connection. The general rule of thumb is that web-page size should be 50 -80 Kb per page, so if you plan to put two pictures on the page their file size should be around 30 KB each.


• Flash, Macromedia (www.macromedia.com) Audio files Sometimes you would like sound included in a presenta-

tion. There are several ways you can do this. Most windows programs have the capability of recording sounds and utiliz-ing them in presentations. Also, Power Point has the ability to provide narration to a slide show. A point to remember is to not embed the sound file into the presentation itself be-cause it will make the presentation too large and you will not have the ability to edit the file. Another possible method of collecting sound is through a digital video recorder. Once this has been done the video can be discarded and only the audio portion used. Transferring a recording from an analog source can be done by using a male-to-male connection from the earphone jack to the microphone jack. Generally, most narration will need some editing to remove any pauses or mispronounced words. There are several software programs available that can accomplish this. It is possible to open the sound file and remove and replace words or sentences and to combine files. Some of the audio editing programs are rather sophisticated and are expensive. However, there several programs available with options to do most of the audio editing needed for web presentations. These programs are:

• Live Motion, Adobe (www.adobe.com)

3D Modeling and Animation Everyday we interact with a three dimensional (3D)

world. Therefore, seeing things this way is intuitive to us. It only makes sense that the ideal way to interact with graphi-cal computer data should also be in three dimensions. In-stead of seeing flat pictures, things can be moved, rotated, and examined closely just as in real life. In order to do this within the computing environment, objects must be mod-eled within the computer itself or scanned into the com-puter.

Modeling 3D objects is one major function 3D software serves. Modeling objects most commonly consists of points and polygons. Points are just that, a single point in 3D space. A polygon is at least 2 points connected to make a line or 3 points or more to make a plane. Many polygons combined can construct the likeness of an object within the computer. These objects can then be textured to resemble real life objects more closely and be animated. These an-imations can be rendered, at the users desired resolution, as movie files of various formats. 3D software is also used to make still images. The advantage to this is once you have a 3D object created, it can be lit in any way and rendered out to any resolution desired.

• Cool Edit 2000 (www.syntrillium.com)

• Sound Forge, Sonic Factory (www.sonicfactory.com)

Illustrations The Bovine Myology project relies on CT scanned data, which is then converted to 3D data using a high-end medi-cal imaging software package. We are in the process of constructing an interactive beef carcass that can be rotated and zoomed in on, in different viewing modes. This allows a student to interact with a completely 3D model. One can move and rotate the carcass or skeleton to any angle they wish and overlay muscles in order to learn the animal’s anatomy. Producing interactive 3D requires additional software, this works with the files output from 3D modeling and animation software.

There are many illustration programs on the market. The programs mentioned in the Photo Images section can be used for illustrations as well. However, most of those soft-ware programs will only make bitmap graphics. For small file sizes, it is good to use vector based illustration software. Vector based graphics can then be integrated with Flash, which will be mentioned later. Vector illustration software that is available is:

• Freehand, Macromedia (www.macromedia.com)

• Illustrator, Adobe (www.adobe.com) Three dimensional graphics and animation generally re-

quire powerful hardware. It should be noted, although the use of 3D over the web has grown immensely, it is still very bandwidth intensive. 3D graphics can also be used on CD-ROM and video. Three-dimensional modeling and anima-tion applications available are:

• Corel Draw, Corel (www.corel.com)

Vector Animation Vector graphics based animation programs with full-

screen navigation interfaces, graphic illustrations, and sim-ple interactivity are in an antialiased, resizable file format small enough to stream across a normal modem connec-tion. Animation software of this type is widely used on the Web, both because of its speed (vector-based animations, which can adapt to different display sizes and resolutions, play as they download) and for the smooth way it renders graphics.

• Lightwave 3D, Newtek (www.lightwave3d.com)

• Maya, Alias | Wavefront (www.aliaswavefront.com)

• 3DS Max, Discreet (www.discreet.com)

• Softimage, Avid (www.softimage.com)

These types of animation software allow the user to use any artwork, using whatever bitmap or illustration tool they prefer, to create animation and special effects, and add sound and interactivity. The content is then saved as a file with a .SWF file name extension. Vector based animation is also ideal for CD-ROM and use in video. Vector animation software available is:

• Animation Master, Hash (www.hash.com)

• TrueSpace, Caligari (www.caligari.com)

• FormZ, Auto des sys (www.formz.com)

• Blender, Blender Foundation (www.blender.org)


Some of the interactive 3D applications available:

• Director, Macromedia (www.macromedia.com)

• Axel 3D, Mind Avenue (www.mindavenue.com)

• Blender, Blender Foundation (www.blender.org)

Digital Video Production There are times when video is useful in getting a point

across. The easiest and most popular way is to work with digital video. This requires a digital video camera, and software to edit and compress the video for final delivery. There are many choices available for digital video cameras, keep in mind that the higher priced models will buy you better lens optics and bigger, better, and more Charge Cou-pling Device chips (CCD). The CCD chip(s) in a camera converts the image to digital format and has a direct effect on color reproduction, noise filtering, and resolution. Other features that are important are a high quality microphone and image stabilization. Features that are useless in most situations, but often hyped by companies, are things such as digital effects filters and digital zoom, so it is wise not to base your purchase on these features. There are a wide va-riety of high quality cameras available from major manufac-turers such as Canon, Sony, JVC, etc.

Once video is taken with a digital video camera, the next step is to capture the footage on a computer for editing. Most digital video cameras transfer video to the computer through a firewire cable so it is a requirement to have a firewire port on your computer. Also, all digital video edit-ing software have a capture function built in, which re-quires a lot of hard drive space since digital video generally produces large files. Once the video is captured on the hard drive of the computer, you can begin the editing process. You can add fades, transitions, and titles to the video. Once the editing process is complete, you are ready to export a movie file for your medium of choice. You can export the finished movie out to tape or you can export a compressed version for the web or CD-ROM. Some of the digital video editing software available is:

• Premiere, Adobe (www.adobe.com)

• Final Cut Express, Apple (www.apple.com/finalcutexpress/)

• Pinnacle Edition 5, Pinnacle Systems (www.pinnaclesys.com)



More Than Words Tips on Professional Speaking

J. Brad Morgan

Introduction Every time General Colin Powell steps up to a micro-

phone, he earns more than $50,000. The authors of the book entitled, “A Passion for Excellence: The Leadership Difference”, Nancy Austin and Tom Peters have turned their passionate skills into a million dollar industry catering to fast-thinking, forward looking executives. What do these people know about presenting that you don’t? Not much, yet each has developed a personal cache of secret strategies and techniques that have helped them become successful presenters they are today. What do these people know about professional speaking that you don’t? Certainly, I don’t consider myself in the same league as these speakers; however, I can give you a few brief secrets that will hope-fully improve your speaking arsenal.

Channel Your Nervousness A great deal of work must be done prior to stepping be-

hind the microphone and in front of a captive audience. It is my personal opinion it is a must that one gets in the right frame of mind prior to speaking one word. I refer to this as “Getting yourself into the spirit of greatness.” In order to overcome and maintain any nervousness, I try to get in the right frame of mind by practicing a talk out loud, not in your mind, and do a rehearsal out loud with an audience of people. These people could include your colleagues, friends, spouse and kids, any interested party. While prac-ticing out loud, I think you should practice using the tech-nology that will be used during the presentation. As the technology gets more and more sophisticated, you need to practice using it. What does that technology include? You will probably have a LCD projector and a computer. If you are using animation, you will want to make sure your lap-

top is fast enough that the animations work well. You can get nervous if you have to wait a while for your screens to change.

Finding The Mix Of Hard Data and Stories I do not consider myself a master storyteller. However,

good storytelling requires more than just having an ear for the dramatic or a compelling delivery. Some audiences re-quire a bigger dose of hard facts, data or statistics fairly early in the presentation so that you can establish a founda-tion of creditability before you can use stories. Interjecting pertinent stories into your presentation allows the speaker to shed the perception that the “O Great One” has entered the room to enlighten the little people. The late Malcolm Knowles (known as the father of adult learning) stated, “That the most important trait of a presenter is that sense of humility that says, I am here as a fellow traveler and we are going to learn together.” We have to remember that good, effective presentations are a partnership and not a mono-logue.

Take Advantage Of Early Arrivals Chatting with early arrivals before a presentation has

many advantages. For example, it helps me connect with some of the attendees and learn a few names, but it also allows me to do quick needs assessment to uncover some of their expectations for the session. Personally, I am not a fan of presenters who lurk in the shadows until they are for-mally introduced. I find it a bit unusual if you act as though you are invisible before the presentation, even though eve-ryone knows who you are. Then, the moment you start pre-senting, you flip a switch and become welcoming and friendly.

Create And Use Visuals I am a fan of visuals as long as they are effective, concise

and easy to interpret. Take this checklist and make sure your visuals meet these suggested guidelines.

• Use readable, consistent typeface. Use sans serif fonts (Arial, Tahoma, Helvetica) for the text on your slide. These font styles are much cleaner and clearer than fonts such as Times New Roman.

J. Brad Morgan Oklahoma State University Department of Animal Science Room 104 Stillwater, OK, USA 74078 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 63-64) June 15-18, 2003, Columbia, Missouri www.meatscience.org


• Limit the text to a few phrases on a screen. A good rule of thumb is six lines down and six words across. If your slides contain more information, try to highlight or animate the most important information.

• Write phrases, not sentences. If you put sentences on your screen, you have nothing to add. Use the phrases as cues to remind you about the additional comments you will add. If you just read the words on the slides and don’t add anything, you won’t come across as an effective presenter.

• Vary the look of the slides: Mix up data slides with charts, pictures, graphs, and bulleted phrases. Incorpo-ration of photographs into your presentation is very ef-fective and establishes creditability for the presenter. Lay out a hard copy of your slides and make sure there is a variety of looks throughout he presentation.

• Use color with care. Choose colors for your screen that convey the appropriate message. Using shades of red used for text is not effective and cannot be seen on your slides.

Conclude With Conviction What would you say about a concert if the last note was

off key? Unfortunately, many presenters end their presenta-tions with the unspoken message that they are glad they are done and now they just want to get out of there. Even if you feel like this, never show your audience. You want to con-clude with style and confidence giving the impression that you could stand up there another hour and be perfectly content. Your conclusion is more important than your open-ing. Your conclusion leads your audience to think about you and your topic after your talk or to forget the entire ex-perience. You must save enough energy to be lively and energetic as you summarize. Here are some ways to con-clude with style:

• Tell a “Just Imagine” scenario. End your presentation with a story about what will happen after your next steps are implemented. Give your audience a clear visual picture about all of the benefits that will occur when they implement your idea, buy your product or engage your services.

• Summarize your major points. You will have your presentation organized around a theme and in that theme you will have two or three points. Under these points you will have presented facts, statistics, pic-tures, etc. to back up those points. When you con-clude remind your audience of your key points.

Manage Questions The vote is split. Some presenters love to be asked ques-

tions as they enjoy the exchanges with the audience. Some presenters want to get up, give their presentation, and not have to answer any questions. Unfortunately, the decision

about whether the audience should be able to ask questions is not usually left up to the speaker. For most presentations, you are expected to answer the questions with charm, grace and a smile on your face. Here are some tips for being an effective question answerer.

• Anticipate potential questions. Prior to your presenta-tion, prepare answers to some questions you think may get asked. Just like the presentation, you should practice saying the answers out loud. One critical note, don’t be nervous before a presentation about be-ing asked the dreaded question. Consequently, you will spend the whole talk waiting for the “dreaded” question.

• Keep energized. Save enough energy so you feel like answering the questions. Pace yourself so you are able to answer questions with energy and excitement.

• Be brief. Answer the question as briefly as possible. In a nutshell, don’t keep talking until the person’s eyes glaze over.

• Be gracious, no matter what. Be respectful to ques-tioners even if their intent is to embarrass you. Your audience will respect you if you answer every ques-tion as a legitimate one.

Take The Leap What separates the really good speaker from the “Just

OK” speaker. How can you move to the next level of pre-senting? Look over this list and start incorporating some of these ideas in your next presentation.

Personalize the presentation to the group. Use examples, stories, visuals, people names, and their products. Talk about their industry. Make your points relevant to their spe-cific interests.

• Tell stories. Audiences love to hear about how some-one else solved a problem, dealt with a crisis, or used a product that gave them great results. Look through your presentation and find two or three places where you can tell a story. Don’t settle for giving your audi-ence just the facts/findings.

• Use emotion when you talk. You probably aren’t be-ing hired to be a motivational speaker, but you are ex-pected to keep your audience awake and alive as you talk. Emphasize words. Share your excitement. Dare to go beyond your usual way of talking. Your audience will love the energy you have.

• Find a coach. A presentation coach can help you get better. As you look for one, you want someone who will nurture your personality. You don’t want to be trained by someone you’re not. If you use visuals, you want the coach to be able to give you ideas on how your visuals can enhance your presentation style.

•



So You Want to Go to Graduate School: What to Consider

Steven M. Lonergan*, Jennifer Leheska & Dave McKenna

In this session we will focus on considerations in the de-cision to pursue a graduate degree, preparation for the next degree while you are an undergraduate, and what to expect out of a graduate education. The decision to go to graduate school has a big impact on your professional career as well as your life. You should ask yourself the following questions before you commit time, effort and money to pursue a graduate degree:

• Should I go to graduate school? • When should I go to graduate school? • Where should I go to graduate school? • How do I prepare for graduate school? • What degree should I pursue? • What is expected of me in graduate school?

Should I Go to Graduate School? The assigned title for this session begs the question of

why you want to go to graduate school. There are many good reasons to pursue a graduate degree in meat science, but there are some poor reasons as well. Most good reasons are centered on the idea that you want to improve your understanding of the application of science and technology in our industry. Your personal career goals also influence this decision. Where do you want to be in 10 years? 20 years? You ultimately have to be the judge of your own an-swer to this question.

When Should I Go to Graduate School? This is a question that many undergraduate students do

not consider. The most common approach is to matriculate directly after completion of the previous degree. This ap-proach is convenient because students are in the “student mode” and usually do not have significant financial obliga-tions. Another approach that works for some is to choose to take an entry-level position in the industry for several years

before pursuing a graduate degree. Students that take this approach have the significant advantage of industry experi-ence and an understanding of the issues that impact success in the meat industry. This perspective allows you to gener-ate your own ideas about what research questions need to be addressed and helps you develop your own program of study in your graduate program. If a student chooses this plan, they need to realize that it will take a lot of discipline to give up a salary to return to school.

Where Should I Go to Graduate School? The answer to this question often has to include personal

and family considerations. The key to making the best deci-sion is to separate the personal and family solicitudes from educational and professional objectives. Ultimately, all fac-tors will have to be considered. The answer to our first question should help you start. Where are the great pro-grams in the disciplines that excite you and fit your profes-sional goals? Talk to your current professors, talk to AMSA professional members and other students. Always consider several programs. Once you have identified several pro-grams, contact faculty at those institutions and plan a cam-pus visit. Sometimes schools will help you with travel ex-penses, but you need to view this as an investment in your future. Once you finish your visit, you should have answers to the following questions.

Many of the questions you may ask during visits will need to cater to your individual goals and expectations. General questions regarding financial issues are appropriate to ask; hopefully, they are not exclusively used to make a decision; but they undoubtedly will play an important role in whatever decision you make.

• Are assistantships available and what do they pay? • Is healthcare insurance provided, including vision and

dental coverage? • What are typical tuition fees for each semester, and is

there departmental assistance with tuition? • Differences in cost of living (especially if you are mov-

ing from one region of the country to another).

You may generate many specific questions regarding programs at each school you visit.

• Inquiries into current and future areas of research.

Steven M. Lonergan Iowa State University 2372 Kildee Hall Ames, IA 50011 E-mail Address: [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 65-66) June 15-18, 2003, Columbia, Missouri www.meatscience.org


• Opportunities to work with extension programs and build industry relationships.

• Opportunities to teach classes or laboratory sections. • Meat science curriculum and other course require-

ments for each program.

Additionally, discussions with current and former gradu-ate students at each program may provide valuable informa-tion in the decision making process.

How Do I Prepare for Graduate School? You should have a list of required courses for the pro-

grams you are considering. The first thing you need to do is make sure you have completed the prerequisite coursework for those core classes defined in the graduate program. This is just a start. Internships, work experience in chemistry, microbiology and meat laboratories, and undergraduate research projects all are valuable components to your preparation for graduate school. Although not specifically required, these experiences make your application for ad-mission in the graduate school more competitive.

What Degree Should I Pursue? The answer to this question is in your career goals. If you

want to be a faculty member at a University or a Director of R&D in an industry lab, you will need a Ph.D. degree. If you want your graduate experience to make you more mar-ketable, improve your earning potential, or increase your

technical skills in a new area, a Master of Science degree may be your choice. Although having an M.S. degree is not a requirement to pursue a Ph.D., most would agree that the M.S. experience is a valuable preparation for a Ph.D. de-gree.

What is Expected of Me in Graduate School? Expectations from different programs vary. One thing that

you can count on is that graduate school is a significant step up in rigor and work from your undergraduate studies. Many students expect to be responsible for their course work and research project. However, contributions to the efforts of the department and meat science program are also expected through extension, teaching and other research projects. Beyond generating new technical information through your own research, the development of teamwork and leadership skills are valuable outcomes of any graduate program.

Conclusion The motivation to go to graduate school has its founda-

tion in our intellectual curiosity and drive to excel. A graduate degree is a means to reach our professional goals. It is a personal and a very serious decision. No person or discussion session can make the decision for you. Our goal in this session is to stimulate you to think critically about your professional career.



The Facts About Beef Cattle Growth Enhancement Technology

James W. Lauderdale

Introduction Research, published in peer reviewed scientific journals

and reviewed by regulatory agencies during the past more than 40 years, demonstrated that beef cattle growth en-hancement products, when used consistent with their label, are safe for the animal, safe for the beef consumer, safe for the environment and deliver significant economic benefits to the beef producer and to the consumer. The USA has the Food and Drug Administration Center for Veterinary Medi-cine (FDA/CVM) product approval process in place that assures such products are safe for the animal, consumer (human food safety) and environment when used consistent with the label. In the USA the label use of growth en-hancement products is encouraged and the illegal use is minimized/prevented through fine/imprisonment for misuse, inspection, no economic incentive to use illegally, and user education programs. If the beef cattle growth enhancement products are safe and effective, why is there a need to ad-dress this topic?

The European Union (EU) banned, in 1989, import of “hormone treated beef” from the USA. In retaliation, the USA imposed, in 1989, ad valorem trade sanctions on im-port of EU goods into the USA, the value of the ad valorem being comparable to the lost trade in beef exports to the EU. This issue was brought to the World Trade Organization for resolution in 1995, however, both the EU ban on import of USA beef and the USA ad valorem trade sanctions remain in place. Presentations, such as, “How safe is that burger” (Consumer Reports, November 2002, p.29-35), “Hormones: Here’s the beef” (Science News, Volume 161, January 5, 2002, p.10-12), “Beef-back to the future” (University of California Berkeley Wellness Letter, February 2003), and the CBS evening news report (May 20, 2003) on a possible connection between zeranol (Ralgro) as a beef cattle growth

enhancing product and potential human health risk have elicited questions and concerns from a variety of people in the USA. In an attempt to address valid concerns as well as allegations and half-truths that raise questions in the pub-lic’s mind about growth enhancing technologies used in beef production in the USA, a focus group was convened to identify issues of concern to the public and to the beef pro-ducing industry.

The focus group identified six key issues of concern to the “public.” Individuals (20) representing beef production, beef product sales, beef industry communications, and growth enhancement product manufacturers discussed how best to address these six key issues. Agreement was reached to address the six key issues identified by the focus group with “single page” responses for each issue. The six issues are addressed in this presentation.

The Six Issues Issue 1. Does the use of growth promotants make our beef less safe or less healthy?

The use of growth promotants does not have a negative impact on the safety, nutritional value or healthfulness of the beef we produce. The safety of the use of growth pro-motants is assured by the product approval procedures re-quired by the FDA/CVM as well as by the on-going testing policies and procedures administered by the Food Safety Inspection Service (FSIS), a division of the USDA. The FSIS regularly tests for residues in meat that would indicate mis-use. Violative residues have not been found.

1. All growth-promoting products must be approved by the FDA/CVM under the New Animal Drug Applica-tion (NADA) procedure. Approval is granted only af-ter rigorous and extensive scientific tests, similar to the tests the FDA/CVM requires for human drug ap-proval.

2. Each NADA is evaluated for safety of use in the target animal, safety to the environment and effectiveness of the product in the target animal. Unlike human drug applications, the NADA is also evaluated for human food safety. All meat products must be safe for human consumption.

James W. Lauderdale Lauderdale Enterprises, Inc. 16700 East B Avenue Augusta, MI 49012 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 67-69) June 15-18, 2003, Columbia, Missouri www.meatscience.org


3. Growth promoting products have been on the market for more than 40 years and there has never been any negative impact on human health.

4. Hormones, like those in growth promoting products, are naturally occurring and are found in all plants and animals, including humans. For example a serving of milk contains 9x the level of hormones as a serving of beef from an implanted steer—a serving of cabbage 710x and soybean oil 7466x. The average man or woman produces 35,000x the hormones every day!

5. Hormones are essential to the proper functioning of many bodily functions including, reproduction, growth, immune system response, as well as the func-tioning of the nervous and digestive systems.

6. Some growth promotants act as a partitioning agent and actually increase the amount of lean red meat and decrease the amount of fat in the beef we con-sume.

Issue 2. Does the manufacture and use of growth promo-tants have a negative impact on the environment?

The production and use of growth promotants does not have a negative impact on the environment, in fact, growth promotants are environmentally friendly.

Impact on Land Use: Because the use of growth promotants improves the efficiency of beef production, there is less stress placed on the environment. The increased efficiency results in more beef produced per cow unit and more effi-cient use of both grasslands and grain-farm acres. As a re-sult, more land is made available for other uses and fewer acres need to be treated with agricultural chemicals.

Example: Performance studies document that, overall, growth promotants increase feed efficiency by 10 percent and rate of growth by about 15 percent. These performance improvements equate to a 21-bushel reduction in the amount corn required to grow a steer or heifer to market weight. The net result of growth promotant efficiencies is that each year, 3 million fewer acres of corn are required to produce the United States beef supply.

1. The world’s land mass is constant, yet a growing population increases the need for more spared land as well as for greater food production.

2. Growth promotants increase production efficiency, which equates to fewer acres diverted from natural habitat to production agriculture.

3. Growth promotants decrease the amount of Nitrogen, Phosphorus, Potassium and other minerals introduced into the environment; this reduction is achieved both through reduced acreage of grains required for beef production and decreased quantity of feces and urine as a result of the increased feed efficiency.

Environmental Impact Studies. Production of growth promoting products is subject to rigorous scientific exami-nation prior to FDA/CVM approval. The manufacturer must

clearly demonstrate that the manufacturing process does not introduce harmful substances into the air, water or land. In addition, the manufacturer must measure and prove that the product and its metabolized by-products do not harm the environment in any way.

4. Excretion of both product and metabolites are meas-ured and documented.

5. Physical and chemical properties and partitioning into water and soil as well as degradation in water and soil are documented.

6. Degradation of the product and its metabolites by mi-crobes is also measured and documented.

7. Effects on both aquatic and terrestrial species are documented.

8. Predicted concentrations of the product and its me-tabolites in water and soil are computed.

9. No growth promotant products are licensed until the risk assessment is completed satisfactorily.

Issue 3. Do growth promotants have a negative impact on an animal’s health or well-being?

The use of growth promotants does not have a negative effect on an animal’s well-being or on an animal’s welfare.

10. Beef producers continue to adopt scientifically based production practices including the most elabo-rate and humane handling equipment.

11. Beef producers follow science-based animal hus-bandry practices.

12. Beef producers feed their animals science-based, healthy and well-balanced rations. As a result cattle remain healthy and efficient in their use of feedstuffs.

13. Beef producers and their veterinarians monitor the health of individual animals on a daily basis.

14. Beef producers ensure that the “five freedoms” are provided for every animal in their care including the ability to turn around, groom themselves, lie down, get up and stretch their limbs without difficulty.

15. Growth promotants increase the animal’s appetite ensuring that the animal remains healthy and well fed.

16. It is in the producer’s best interest to provide an ideal environment for the health and safety of their animals.

Issue 4. Has the use of growth promotants contributed to the reduction in the number of smaller farms? The use of growth promotants does not provide an economic advan-tage to large, corporate farms nor do they put smaller farm-ers at a disadvantage.

Growth promoting products, including implants, can eas-ily be utilized by all cattle producers, whether they have a few head of cattle or several thousand. The per head, eco-


nomic advantages that growth promotants provide are the same, regardless of the size of the operation. There is no additional economic advantage or benefit for large produc-ers and there is no “cause and effect” between growth pro-motants and the trend to consolidation in the industry.

17. Growth promoting products can be effectively util-ized and are economically rewarding in any size operation.

y.

18. Utilizing science and technology in beef produc-tion results in lower beef prices and a continuous supply of top quality beef for consumers.

19. There is a trend to fewer, larger feeding operations; however, cattle feeding operations of all sizes con-tinue to utilize growth promotants as they successfully produce beef for the market.

20. No cause and effect has been identified between growth promotant products and the trend to consoli-dation in the beef industry.

Issue 5. Do growth promotants really benefit the beef indus-try? Improved production efficiency benefits the entire beef industry as well as consumers.

The use of growth promoting products improves both growth and feed efficiency, which is of benefit to both beef producers and consumers. For example, proper use of im-plants improves both average daily gain and feed efficiency, which results in an economic benefit of approximately $40 per beef animal. This lower cost of production results in lower beef prices to the consumer, and keeps beef more price competitive compared to other protein sources.

21. Research by Gill and Trapp (1997) indicated that without the efficiencies that implants provide, beef’s share of the protein market would decrease from 31.9 percent to 29.8 percent. The decrease in market share would decrease beef retail sales by $1.4 billion, eliminating the need for 1.2 million cows (the number of cows in the entire state of Oklahoma).

22. The use of growth promotants help produce a more consistent, better managed beef product, without sacrificing taste or qualit

23. Growth promotants give consumers the healthy, flavorful, nutrient dense beef they demand at a price they can afford.

24. Eliminating the use of growth promoting implants in the United States would not increase beef exports to Europe. The European ban on implanted beef is based on politics and agricultural protectionist pro-grams and would not be lifted if the United States beef producers quit using hormones. The EU is cur-

rently importing beef from South America where there is widespread hormone use.

Issue 6. If there are any questions at all about growth pro-motants, why take a chance?

The European “Precautionary Principle” (action should be taken to correct a problem if there is any evidence that harm may occur…the foresight to protect against any possi-ble harm) does not recognize scientifically based risk as-sessment and analysis as being adequate and, therefore, is very limiting for the adoption of any new technology, not just animal health products and technology. The precau-tionary principle that guides our FDA/CVM is based on ex-tensive, thorough, conservative scientifically based re-search.

25. The USA FDA/CVM approval process is very con-servative in their approval of growth promotant prod-ucts.

26. Growth promotant products are approved only af-ter a thorough review of validated, well-supervised, rigorous scientific studies.

27. This thorough, cautionary product approval proc-ess assures that the products that are approved for sale will not have any adverse effects on human health, animal health or environmental safety.

28. Beef from cattle implanted with growth promotants is now being eaten by a third generation of consum-ers without any negative impact on their health.

29. “We inspect what we expect”…A thorough, on going inspection process ensures that there are no product misuses or violations and that all products are used according to their labeled and intended use.

30. The scientific principles that govern our approval process make new technologies and new procedures possible.

Conclusions Beef cattle growth promotion products, when used con-

sistent with their label, are safe for the animal, safe for the beef consumer, safe for the environment and deliver signifi-cant economic benefits to the beef producer and to the con-sumer. In the USA, use of growth promotion products should be based on sound business decisions and should not be influenced by political and social pressures. Anti-animal production groups will use numerous bases to dis-rupt beef consumption and beef production in the USA, including the “selling of fear” related to endocrine disrup-tion, carcinogenicity, adverse effects in humans, environ-mental contamination, and misuse/abusive use of the prod-ucts.



The National Pork Quality Benchmarking Study

David J. Meisinger

Abstract The 2002-03 Benchmarking Value in the Pork Supply

Chain Project was conducted to evaluate the status and the progress of the pork industry since the first National Pork Quality Audit conducted in 1993-94. The project was a cooperative effort between the National Pork Board and several industry partners and was conducted by the Ameri-can Meat Science Association in cooperation with Colorado State University, the University of Illinois and Texas A & M University. The project was done in four phases: an industry survey, processing component, a retail segment, and an industry strategy workshop.

In Phase I, pork processing companies were surveyed to identify, quantify and rank factors influencing pork quality. Surveys were designed to determine the quality of pork cur-rently at the slaughter and fabrication segments of the pork chain. Meat processors provided slaughter information based on 64% of the 98 million barrows and gilts slaugh-tered in federally inspected plants in 2002. All major hog-producing areas of the U.S. were represented. Based on a dollar value, results of the survey indicated that the primary concerns about pork quality at the packing level were; (1) inconsistent weights; (2) thin bellies; (3) pale, soft and exu-dative (PSE); (4) too fat carcasses; and (5) ab-scesses/injection sites. Survey results were used to deter-mine costs associated with quality deficiencies. It was esti-mated that $8.08 or approximately 8% of the live-animal value is lost per slaughter barrow/gilt due to quality variabil-ity.

In Phase II, the objective was to evaluate the effects of PSE pork on the production of boneless and bone-in hams and to investigate the effect of belly thickness on processing and slicing yields as well as consumer satisfaction. The ham primals were selected and shipped through normal chan-nels to a ham processing facility. The hams were catego-rized into low PSE, medium PSE, and high PSE groups. The

results showed that color and water holding capacity gener-ally followed normal patterns with the high pH product generally having lower L* values and lower drip loss. The values calculated for pack-off yield (after slicing and pack-aging) and final yield were clearly in favor of the high pH (low PSE) hams. Clearly, the low PSE group outperformed the rest of the treatment groups in that it had the lowest mi-nor and major defects and the highest percentage of no de-fects. The sensory panelists demonstrated through purchase intent that they preferred the low PSE product two to three times that of any other treatment. The belly data showed that the thinner bellies had higher percentage cook shrinks and lower overall final yield percentages than the thick bel-lies. However, the results of this study showed that con-sumers prefer leaner bacon when evaluating or purchasing it visually and experience very minimal differences in ac-ceptability and purchase intent based upon palatability.

In Phase III, the objective was to characterize retail prod-ucts from the loin (enhanced and non-enhanced), ham (boneless), and belly (not-fully-cooked bacon), assessing the implications of quality on prices charged by retailers and to determine the opportunities lost with pork quality defects. Retail packages of boneless loin chops, bacon, and ham were purchased at retail markets in eight major U.S. cities which were chosen to provide broad geographical repre-sentation across the United States. Twenty-five retail stores in each city (n=200) were visited. Across all retail stores visited, average retail case displays consisted of 64.3% processed meats, 8.0% fresh poultry, 7.9% bacon, 6.8% fresh beef, 3.5% fresh pork, 2.6% heat and serve products, 2.4% ham products, and 2.4% frozen poultry products. Approximately 13% of the boneless pork chops found in the retail display were characterized as being of “poor quality.” Overall, boneless loin chops had a mean NPPC color rating of 3.52 and were characterized as having a reddish-pink colored lean. Across all loin chops collected, the mean peak WBS force was 2.96 kg. Trained sensory panel mean overall tenderness ratings were 5.95, ranging from 4.25 to 7.75 on an 8-point scale for all chops evaluated in the study. The study also found that enhanced product offers organoleptic benefits in juiciness and tenderness, but is more frequently associated with off-flavors than non-enhanced product. Off-flavors most encountered by the panelists included salty, metallic, sour, and rancid/oxidative flavors.

David J. Meisinger National Pork Board P.O. Box 9114 Des Moines, IA 50306 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 71-72) June 15-18, 2003, Columbia, Missouri www.meatscience.org


For the ham data, mean panelist ratings for juiciness, tenderness, texture, and ham flavor intensity were all be-tween 5.36 and 5.83. The most frequently detectable flavor was salt, with an average rating of 1.20. Mean price for each type of ham differed (P < 0.05) from each other, indi-cating mean retail prices ($/kg) for ham with natural juices, ham with water added, and ham and water product were $2.10, $1.92, and $1.60, respectively. Trained panel ratings for juiciness and tenderness were highest (P < 0.05) for ham and water product, followed by ham water-added and, lastly, ham with natural juices. Texture scores favored ham products in exactly the reverse order. Flavor intensity and smoke flavor ratings for ham with natural juices was higher (P < 0.05) than both ham with water added and ham and water product.

From the bacon data, it was determined that, contrary to previous hypotheses by the authors, no significant differ-ences between lipid content, lipid quality, or palatability characteristics were found to occur among price categories. However, it is suggested that the highest priced national brand bacon was a more consistent product, as indicated by the least variation in percent lipid (DM), panel crispiness, chewiness, and smoke flavor intensity ratings.

Phase IV represented the strategic analysis of the data. Using results of the SWOT analysis, these are strategies that could be implemented by the U.S. pork industry to improve the “quality” of its products:

1. Continue industry progress in attending to, and im-proving upon, pork quality shortfalls previously iden-tified in the National Pork Chain Quality Audit—1992

and presently elucidated in the National Pork Chain Quality Audit—2002, especially focusing upon im-proving the consistency of weight, composition and quality of U.S. pork.

2. Improve the amount and quality of communication among those in different sectors of the pork produc-tion chain to assure availability of sufficient informa-tion to allow for corrective actions to improve further the acceptability of U.S. pork.

3. Great progress has been made in improving lean meat yields, but further reductions in backfat thickness may be counterproductive because too many hogs are now too lean (generating problems with performance, productivity and reproduction) and too many car-casses have unacceptable quality (bellies that are too thin and cuts with too little marbling).

4. Industry must develop clear economic signals for eas-ily and objectively measuring “quality,” along the production chain, to facilitate coordinated focus on generating pork to meet domestic and global, sea-sonal and geographical, consumer demands for fresh, enhanced, processed, consumer-friendly, value-added and ready-to-eat products.

5. Industry must assure that appropriate attention is paid to animal welfare, food safety, introduction of Foreign Animal Diseases, environmental issues, competing animal-protein sources, non-meat protein sources, U.S./world economies and potential opportunities for international cooperation in global marketing of “North American” pork.



Enhancing Meat Color Stability

Donald H. Kropf

Meat color stability is affected by numerous decisions and circumstances that begin with live animal selection and breeding, and include nutrition, environment, handling, holding conditions before slaughter, stun/bleed variables, chilling protocol, aging, holding time and conditions (espe-cially temperature), fabrication conditions, time from fabri-cation to packaging, successful packaging, type of packag-ing; storage, distribution and handling of product, display conditions and handling by customers. The above apply to fresh, chilled, frozen and to cured products. Enhancements to chilled non-cured meat can markedly influence color stability. Cured meat is additionally affected by added in-gredients, physical manipulation conditions, time and tem-perature protocols for smoking and heat processing and post-cook chilling and packaging. Those who troubleshoot color stability problems tend to concentrate on the most recent events but color could be affected in many places in the livestock to product to consumer chain.

DeoxymyoglobinFe++

DeoxymyoglobinDeoxymyoglobinFeFe++++No O2

OxymyoglobinFe++

OxymyoglobinOxymyoglobinFeFe++++ATM O2

Reduced Fe Desirable

+O2

+O2

+e-

+O2

+e--O2

-e-

-O2

-e-

+O2 -e-+O2 -e-

-O2 +e--O2 +e-Low O2

Oxidized Fe Undesirable

MetmyoglobinFe+++

MetmyoglobinMetmyoglobinFeFe++++++

Hunt 1993 Figure 1. Fresh meat color triangle.

Meat color basics will be reviewed. First, understanding the meat color triangle is very important. Muscle tissue ap-pearance is determined by the chemical state of muscle pigments (Figure 1). In the absence of oxygen, pigment is in the deoxymyoglobin state, which has a dark, purplish-red color (Kropf, 2000). On exposure to air, the pigment is rap-idly oxygenated to form oxymyoglobin, the bright red that consumers have been taught to expect and find attractive. Deoxymyoglobin and oxymyoglobin, which are both in the

reduced state, can oxidize to metmyoglobin, which has a dull brown color associated with deterioration of quality. Metmyoglobin is more stable and is slowly converted to deoxymyoglobin by enzyme-mediated reactions termed metmyoglobin-reducing activity. Muscle tissue that is defi-cient in the enzymes that mediate metmyoglobin reduction or in reduced cofactors necessary for reduction is unable to reconvert metmyoglobin, which then persists. Muscles vary widely in metmyoglobin-reduction activity, and it dissipates during storage of muscle. Those that tend to have a high activity, such as the longissimus dorsi, are more color-stable in air, their red color persisting for 3 or 4 times as long as unstable muscles of low metmyoglobin-reduction activity.

Partial oxygen pressure (PO2) plays an important role in determining which chemical state of heme pigments, pri-marily myoglobin, is favored at any muscle location (Figure 2). Formation of undesirable brown met forms of heme pigments occurs most rapidly at intermediate PO2 with peak activity at 4 mm but ranging from 1.4 to about 25 mm PO2. Thus, partially oxygenated heme pigments discolor faster than completely deoxygenated or with a higher level of oxygenation.

OxymyoglobinOxymyoglobinDeoxymyoglobin

0 5 10 15 20Oxygen, %

% M

b Fo

rm

0

100

0 5 10 15 20Oxygen, %

% M

b Fo

rm

0

100

MetmyoglobinMetmyoglobin

Figure 2. Partial oxygen pressure and myoglobin form.

Color stability is more achievable if myoglobin remains as deoxymyoglobin until bright red or bright pink is re-quired to satisfy meat purchasers. Unnecessary and uncon-trolled pigment changes are costly in terms of losing ability to return to deoxymyoglobin and shorten color life. Using fresh rather than tired raw material to produce a cured product also contributes to improved meat color stability.

When the new cut surface is formed, oxymyoglobin quickly forms at the surface and gradually penetrates more deeply as oxygen diffuses into the muscle, resulting in the gradual blooming. The depth of oxygen penetration into

D. H. Kropf 247 Weber Hall Kansas State University Manhattan, Kansas 66506-0201 Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 73-75) June 15-18, 2003, Columbia, Missouri www.meatscience.org


muscle is dependent on oxygen diffusion, which is influ-enced by temperature as well as pH. Although oxygen dif-fusion is more rapid at a higher temperature, net oxygen penetration is greater at temperatures close to 0°C, where activity of enzymes that use oxygen is minimal. At higher temperatures, respiratory enzymes use more oxygen and limit its penetration into muscle. Respiratory enzyme activ-ity is favored by higher pH, consequently high-pH muscle utilizes more oxygen, and so less oxygen diffuses into mus-cle. The result is a darker colored muscle, which has only a very thin layer of oxymyoglobin on the surface; conse-quently the color is primarily that of the subsurface de-oxymyoglobin. High partial oxygen pressure in the gaseous environment surrounding the muscle will cause the oxymy-oglobin layer to move into the muscle more rapidly and more deeply. Relatively fresh muscle with a good supply of reducing capability will have two pigment layers, oxymy-oglobin on the surface and deoxymyoglobin at deeper loca-tions. For intact muscles, oxygen diffuses more deeply with increasing time after initial exposure to air for several days, depending on the mini-environment surrounding the mus-cle and the supply of reducing capability of the muscle. When reducing mechanisms of muscle approach depletion, a third layer of pigment, brown metmyoglobin, forms be-tween the oxymyoglobin and deoxymyoglobin layers. The brown area has the intermediate PO2, which favored its formation. The oxymyoglobin layer becomes thinner and the metmyglobin layer becomes thicker and moves closer to the surface. Ultimately both visual observers and reflec-tance instruments begin to see the brown discoloration. Color stability can be influenced by:

Live Animal Selection - Stress resistant may favor slower pH decline, less oxidative meat.

Nutrition - Vitamin E (tocopherol) feeding creates more color stability, even for higher unsaturated fat diets, and longer aging, and influences pork and turkey in a similar direction (Liu and others, 1995; Buckley and others, 1995).

Environment - Severe conditions may cause dark cutters. A sudden temperature rise during cool spring days can af-fect pigs and turkeys and cause more oxidative, discolora-tion-prone muscle.

Handling - Cattle and pigs are vulnerable to hot tempera-ture and to mixing of animal groups. Hauling at night advo-cated, also keeping animal groups intact. Conditions that distract/startle animals can cause stress (Faustman and Cas-sens, 1990).

Holding Conditions - Pigs should be rested before slaugh-ter, allowed to cool, have access to water for 3 to 4 hours after unloading. Too short or no holding encourages PSE and too long (over 6 hours) may increase DFD.

Stun/bleed Variables - Effective stunning including proper placement, appropriate current for electrical and stun appli-cation time influence quality. Bleeding quickly after stun-ning is also essential. Carbon dioxide may be good system.

Dressing/chilling - More rapid chill translates to color stability as low temperature slows pH decline, pigment oxi-dation and facilitates a deeper oxymyoglobin front.

Aging - While longer aging (14 to 28 days) encourages faster discoloration, a ripening time of five to seven days facilitates blooming and lengthens display life.

Fabrication/Enhancement/Packaging - Minimize light ex-posure and time from fab to packaging.

Added Ingredients - Those that may improve color stabil-ity (Miller, 1998) include sodium, potassium or calcium lactate; ascorbic acid or sodium isoascorbate, carnosine, anserine, phenolic antioxidants, rosemary and its extrac-tives, and other plant source materials. Those that may di-minish color stability are alkaline phosphates, salt, water contaminants, ascorbic acid or sodium isoascorbate, or-ganic acids, and heavy metals.

Packaging (Kropf, 2000) - High-oxygen MAP systems of-ten have atmospheres of 20% carbon dioxide and up to 80% oxygen, produce and maintain a desirable red color in beef for up to 9 days and depress metmyoglobin formation by driving oxygen deep under the surface of meat. Ground beef in a similar treatment was stable for 6 days. Pork loin chops in high oxygen had acceptable saturation indices and display color for 8 to 12 days. Odor, not color may limit this system. Carbon monoxide has been used in beef MAP systems to maintain a bright cherry-red color (Sorheim and others, 2001). Carbon monoxide binds strongly to myoglo-bin and hemoglobin, forming stable bright-red compounds. Beef loin eye steaks at 4°C in a 0.4% carbon monoxide, 60% carbon dioxide, and 40% nitrogen system, compared with a high-oxygen (80%) system or vacuum packaging, were brighter red and had better display color stability. This does not mask microbial deterioration and is approved as a master pack system in the U.S.A.

In ultra-low oxygen MAP, a slight amount of residual oxygen frequently occurs due to small pockets of air not removed initially by evacuation or flushing. These fre-quently cause major discoloration, reduced color stability, or blooming ability problems. Initial oxygen concentrations >0.15% (1,500 ppm) seriously compromised color stability of beef and lamb. Pork was affected by residual oxygen concentrations >1.0%. Oxygen scavengers are needed to get residual oxygen low enough and fast enough as muscle scavenging of oxygen is inadequate and slow. For cured product, nitrogen gas is used with a goal of diluting residual oxygen to 0.5% or less.

Lighting (Faustman and Cassens, 1990; Kropf, 1998) - Time and intensity of meat product exposure to light during processing, storage and distribution should be minimized. Display lighting is essential for marketing but its effect on discoloration by temperature elevation, photochemical oxi-dation and sub-optimal color rendition can be minimized by selecting fluorescent lamps of 2900 to 3750° Kelvin and using least intensity which is compatible with effective dis-play. Color display at 32°F is effective in enhancing display


life. Ultra-violet is detrimental to meat color, especially shorter wavelengths (Bertelsen and Skibsted, 1987) but packaging can block this effect.

Temperature - Cold at proper times is absolutely essential to minimizing product value loss. A comprehensive ground beef study (Mancini, 2001) gives display life as influenced by storage time and by temperature of storage and display. Coarse ground beef in chubs stored and displayed at 32°F benefits dramatically and is cost effective. The least product price discounting or loss saved $283 per week for a store selling 2000 lbs. ground beef per week. This information led to the “32° Makes a Difference” program by a major packer. In a companion study, half of meat display tempera-tures were at 39°F or warmer. Audits International (1999) surveyed actual retail temperatures for refrigerated foods including fresh meat, prepackaged lunchmeat and deli counter meat. Data from primary shoppers of over 1000 households geographically dispersed across the country showed one in two refrigerated product temperatures were over 41°F, one in four were over 45°F, and 1 in 17 were over 50°F. All types of cases had product above 41°F with frequency of this occurrence ranging from 27% for fresh meat to 71% for the deli counter. Mean and maximum temperatures reported were 43.6 and 66°F for prepackaged lunch meat, 44.8 and 64°F for deli counter meat and 39.2 and 58°F for fresh meat, with the worst 10% above 50°F for prepackaged lunch meat and deli counter meat.

Product temperatures rise about 8 to 10°F during a typi-cal summer shopping excursion. The worst 5% of shopping conditions showed product temperatures increased 15 to 20°F on the way home from shopping. This data is very alarming and indicates that the entire meat product market-ing chain needs to minimize problem temperatures. Shop-per education should emphasize proper handling of meat and other perishables.

Consumers judge acceptability of meat largely on ap-pearance, mostly color, of exposed muscle. Dull and/or discolored fat, purge or bone cut surfaces detract from meat cut appearance but their good appearance cannot compen-sate for discolored muscle. Longer storage (Warren and oth-

ers, 1992) can result in greenish pork fat. Feeding cattle diets high in some unsaturated fat can result in “dirty” look-ing discolored spots, possibly more pronounced with high oxygen.

Black vertebra have been caused by ultra-chill in pork. Freezing poultry may cause black bones. Bones on beef cuts are more black in high oxygen packages but also noted in polyvinylchloride film packages, always in the bone mar-row or porous bone structure. Antioxidant or vitamin C treatment may diminish this problem.

References Audits International (1999) U.S. Cold Temperature Evaluation. Available at:

http://www.am.f.org/CompletedProjects.htm.

Bertelsen, G.; Skibsted, L. H. (1987) Photooxidation of Oxymyoglobin. Wavelength Dependence of Quantum Yields in Relation to Light Dis-coloration of Meat. Meat Sci. 19:243-251.

Buckley, D. J.; Morrissey, P. A.; Gray, J. I. (1995) Influence of Dietary Vi-tamin E on the Oxidative Stability and Quality of Pig Meat. J. Anim. Sci. 73:3122-3130.

Faustman, C.; Cassens, R. G. (1990) The Biochemical Basis for Discolora-tion in Fresh Meat: A Review. J. Muscle Foods 1:217-243.

Kropf, D. H. (1998) Meat Case Lighting Facts. National Pork Board, Des Moines, IA.

Kropf, D. H. (2000) Meat, Modified Atmosphere Packaging. Encyclopedia Food Sci. & Technol., John Wiley publ., New York.

Liu, Q.; Lanari, M. C.; Schaefer, D. M. (1995) A Review of Dietary Vitamin E Supplementation for Improvement of Beef Quality. J. Anim. Sci. 73:3131-3140.

Mancini, R. A. (2001) Effects of Lean Level and Storage and Display Condi-tions on Ground Beef Color and Microbiology. M.S. Thesis. Kansas State University, Manhattan.

Miller, R. (1998) Functionality of Non-Meat Ingredients used in Enhanced Pork. Facts, National Pork Board, Des Moines, IA.

Sörheim, O.; Nissen, H.; Aune, T.; Nesbakken, T. (2001) Use of Carbon Monoxide in Retail Meat Packaging. Proc. Recip. Meat Conf., Am. Meat Sci. Assn, Savoy, IL. 54:47-51.

Warren, K. E.; Hunt, M. C.; Marsksberry, C. L.; Sörheim, O.; Kropf, D. H.; Johnson, D. E.; Windisch, M. J. (1992) Modified-Atmosphere Packaging of Bone-In Pork Loins. J. Muscle Foods 3:283-300.



Carcinogens Formed When Meat is Cooked

James S. Felton*, Cynthia P. Salmon, Mark G. Knize

Introduction Diet has been associated with varying cancer rates in

human populations for many years, yet the causes of the observed variation in cancer patterns have not been ade-quately explained (Wynder et al., 1977). Along with the effect of diet on human cancer incidence is the strong evi-dence that mutations are the initiating events in the cancer process (Vogelstein et al., 1992). Foods, when heated, are a good source of genotoxic carcinogens that very likely are a cause for some of these events (Doll et al., 1981). These carcinogens fall into two chemical classes: heterocyclic aromatic amines (HAA) and polycyclic aromatic hydrocar-bons (PAH). There is ample evidence that many of these compounds are complete carcinogens in rodents (El-Bayoumy et al., 1995; Ohgaki et al., 1991).

Heterocyclic aromatic amines are among the most potent mutagenic substances ever tested in the Ames/Salmonella mutagenicity test (Wakabayashi et al., 1992). Both classes of carcinogen cause tumors in rodents at multiple sites, (El-Bayoumy et al., 1995; Ohgaki et al., 1991) many of which are common tumor sites in people on a Western diet. An HAA, PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), and a PAH, B[a]P (benzo[a]pyrene), of compa-rable carcinogenic potency caused mammary gland tumors in a feeding study in female rats (El-Bayoumy et al., 1995). In addition, PhIP has recently been shown to cause carci-nomas in the prostate of the male rat (Shirai et al., 1997). Complementing the rodent cancer studies are numerous human case-control and prospective studies suggesting a relationship between overheated beef, chicken, and lamb, and cancer of the colon, breast, prostate, and stomach (Sinha et al., 1999; Ward et al., 1997; Zheng et al., 1998).

Thus, it is important to estimate human exposure to the HAA and PAH food carcinogens by accurate dietary intake

data to determine the amounts and types of carcinogens to which humans are exposed.

Formation The cooking process is responsible for the formation of

HAA and PAH from natural constituents in foods, with cooking time and temperature being important determinants in both the qualitative and the quantitative formation of these compounds (Knize et al., 1985; Skog et al., 1995). Higher temperatures and longer cooking times favor the formation of HAA. A number of studies have shown the precursors for the formation of the HAA to be amino acids, such as phenylalanine, threonine, and alanine; creatine or creatinine; and sugars (Skog et al., 1993). HAA are fre-quently formed in muscle meats during frying, broiling, and grilling. But methods using lower temperatures such as stewing, boiling, and baking usually do not form HAA.

PAH are products of combustion and pyrolysis of protein, carbohydrate or lipids by condensation of smaller units at high temperatures to form stable polynuclear aromatic com-pounds (Lijinsky, 1991). PAH levels in foods are strongly dependent on the method of cooking, including the distance of food from the heat source, design of cooking device and fat content of the foodstuff (Lijinsky, 1991). Smoke deposited on the surface of charcoal-grilled meats appears to be the major source of PAH carcinogens in food.

The HAA and PAH carcinogens formed during cooking have stable multi-ring aromatic structures. The heterocyclic amines have an exocyclic amino group and several nitrogen heteroatoms. Structures of those compounds commonly detected in foods are shown in Figure 1. Additional hetero-cyclic aromatic amines have been found in foods and the whole set of HAA compounds has been reviewed (Rob-bana-Baranat et al., 1996). Over 25 PAH have been identi-fied in curing smoke and approximately 40 others have been identified but not characterized in this type of smoke. An extensive database of PAH in foods was recently pub-lished (Kazerouni et al., 2001). The variables influencing the formation of PAH and HAA create a wide range of concen-trations in food, requiring the analysis of a large number of food samples cooked under various conditions to determine the sources and amounts of carcinogens in the human diet.

James S. Felton Biology and Biotechnology Research Program Lawrence Livermore National Laboratory University of California P. O. Box 808 Livermore, CA 94551-9900 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 77-81) June 15-18, 2003, Columbia, Missouri www.meatscience.org


N N

N NH 2

CH 3

PhIP

N

N N N

NH 2

CH 3H 3 C

MeIQx

B[k]F

B[a]P B[a]A

B[b]F

DBA

Indenopyrene

N

N N N

NH 2

CH 3 H 3 C

DiMeIQx

CH 3

Figure 1. Chemical structures and abbreviated names of HAA and PAH carcinogens. B[a]A= benzo[a]anthracene B[a]P=benzo[a]pyrene B[b]F=benzo[b]fluoranthene B[k]F=benzo[k]fluoranthene DBA=dibenzo[a,h]anthracene DiMeIQx=2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline Indenopyrene= indeno[1,2,3-c,d]pyrene MeIQx=2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline PhIP=2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

Analysis There are several factors that make the analysis of car-

cinogens from foods a difficult problem. PAH and HAA are present in foods at low nanogram per gram levels. The low levels require that chromatographic efficiency and detector sensitivity be optimized, and these are typically analyzed by gas or liquid chromatography with detection by light ab-sorbance, fluorescence or mass spectrometry. Several of the compounds are formed under the same reaction conditions,

so the number of compounds to be quantified requires that the extraction, chromatographic separation, and detection be general enough to detect several of the carcinogens in each separation. A single solid-phase extraction scheme was used to isolate the PAH and HAA classes of genotoxic compounds from charcoal-grilled meat (Rivera et al., 1996), and was developed from an innovative solid-phase extrac-tion method for HAA (Gross et al., 1992).

Results Comparison of the formation of PAH and HAA shows

that open flames are required to make PAH, but high tem-perature by a variety of heat sources can form HAA (Table 1). The mass amounts of PAH and HAA are within the same order of magnitude for high temperature propane-grilling of ground beef with 30% fat by weight. Further work is needed to analyze other food types for both classes of carcinogen. Table 1. Carcinogenic HAA and PAH in hamburgers, ng/g

Propane grilled Charcoal grilled Pan fried MeIQx 2.2 nd* 3.8 PhIP 15 nd 16 B[a]P 6.2 0.6 nd B[b]F 18 4.1 nd B[k]F 2.0 nd nd B[a]A 5.2 3.1 nd DBA 0.5 nd nd Indenopyrene 5.1 nd nd *nd=Not detected.

Reducing the formation of food carcinogens Many studies have shown the effect of cooking time and

temperature on the formation of mutagenic activity (Com-moner et al., 1978; Sugimura et al., 1977) and specific HAA in various meats (Gross et al., 1992; Knize et al., 1985; Skog et al,. 1995). Food doneness is difficult to quantify. In our experience, measuring temperatures with thermocouples is too dependent on probe placement. Surface appearance, too, is not a good doneness indicator because color can be affected by other variables such as pH differences in meat.

Reducing the cooking temperature seems to be the most practical way to reduce HAA content, but avoiding the conditions where the temperatures are below those needed to kill harmful bacteria is also important. The formation of PAH can be reduced by not exposing the food directly to the heat source and resulting smoke when grilling foods (Larsson et al., 1983).

Figure 2 shows two methods that reduce the formation of HAA during cooking of beef patties to an internal tempera-ture of 70°C. The pan temperature was varied and the sum of the detectable HAA measured. When meat patties were turned over just once at 5 min (open bars), and cooked until the internal temperature of 70°C was reached, there was a great effect of pan temperature on the formation of the HAA. If the meat patties were turned every minute during cooking, much less of the HAA was detected. So cooking at a lower surface temperature (160-180°C) and turning the meat over every minute greatly reduces the formation of


HAA when frying ground beef.(Salmon et al., 2000). In the same study it was shown that the time needed to produce a beef hamburger that is safely heated to 70°C is only slightly decreased by increasing the pan temperature from 160 to 250°C (Figure 3). Figure 3 also shows that if meat is turned over every minute, cooking times are slightly reduced com-pared to flipping the meat over just once during the entire cooking time. Thus, a high pan-temperature accelerates the cooking process only a little, but turning every minute both accelerates the cooking and reduces the HAA formation.

0

5

10

15

20

160 180 200 250

Pan Temperature, °C

Het

eroc

yclic

am

ines

, ng

/g

Turned over onceTurned every minute

Figure 2. Sum of HAA formed in beef patties fried to an internal tem-perature of 70°C, either turned over once at 5 min (open bars) or turned over every minute (filled bars) until done. Four different pan temperatures were used. Error bars are the standard deviation of five replicate samples.

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11

Pan temperature

Coo

king

tim

e, m

inut

es

160°C 180°C 200°C 250°C

Turned over onceTurned every minute

Figure 3. Cooking time to reach an internal temperature of 70°C for beef patties fried at a pan temperature of 160, 180, 200 or 250°C, and either turned over once during frying (open bars) or turned over every minute (filled bars). Frying time varied little despite the greatly dif-ferent pan temperature. Turning every minute decreased the cooking time needed.

Another means of decreasing HAA formation is to re-move the precursors from the meat before cooking (Felton et al., 1994). Figure 4, upper, illustrates that ground beef patties contain small molecule precursors of HAA: amino acids, sugars, and creatinine. When fried at high tempera-tures, these precursors form the HAA. Alternatively, a mi-crowave oven pretreatment of 1.5 to 2 min reduces the pre-

cursors, which can be discarded as meat drippings, so meat then cooked at high temperatures results in lower HAA ex-posure to the consumer.

Risk assessment of meat carcinogens The analysis of foods for HAA and PAH is important be-

cause there is widespread human exposure to these com-pounds, there is suggestive epidemiology for cause and ef-fect, and these chemicals are potent mutagens and animal carcinogens as stated in the introduction. Exposures differ among individuals, since dietary preferences and methods of food preparation can vary greatly. This area of research provides a unique opportunity in cancer etiology, the chance to evaluate carcinogens in human populations. The variability in the formation of these compounds also pro-vides the opportunity for intervention, to reduce exposure if it is warranted from risk evaluation of humans and rodents exposed to these compounds in their diet.

Which class of carcinogenic compounds and which spe-cific compounds within each class are the most important in human health are difficult questions to answer at this time. All of the HAA and PAH tested are rodent carcino-gens, so it could be argued that the total mass of carcinogen is the most important risk factor.

The compounds do differ in tumor-site specificity in rats, with most HAA causing tumors at sites commonly seen for humans. The metabolism of each class of chemical and the enzymes involved in their metabolism are known to be po-lymorphic, suggesting a distribution in risk across the popu-lation, varying from individual to individual.

For PAH carcinogens, occupational studies have been used to establish risk of human exposure, with only sugges-tions of excessive risk at some sites (Nadon et al., 1995). The health risk to the human population consuming HAA has been recently discussed (Layton et al., 1995; Zimmerli et al., 2001), and supports the linkage between HAA con-sumption and higher cancer risk.

Acknowledgments This work was performed under the auspices of the U.S.

Department of Energy by Lawrence Livermore National Laboratory under contract no. W-7405-Eng-48, and sup-ported by the NCI grant CA55861 and DOD Prostate Can-cer Research Program grant DAMD 17-00-1-0011.


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References Commoner, B.; Vithayathil, A.J.; Dolara, P.; Nair, S.; Madyastha, P.; Cuca,

G.C. (1978). Formation of mutagens in beef and beef extract during cooking. Science 201: 913-916.

Doll, R.; Peto, R. (1981). The causes of cancer: Quantitative estimates of avoidable risks of cancer in the United States today. Journal of the Na-tional Cancer Institute 66: 1191-1308.

El-Bayoumy, K.; Chae, Y.-H.; Upadhyaya, P.; Rivenson, A.; Kurtzke, C.; Reddy, B.; Hecht, S.S. (1995). Comparative tumorigenicity of benzo[a]pyrene, 1-nitropyrene, and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine administered by gavage to female CD rats. Carcinogenesis 16: 431-434.

Felton, J.S.; Fultz, E.; Dolbeare, F.A.; Knize, M.G. (1994). Reduction of heterocyclic amine mutagens/carcinogens in fried beef patties by mi-crowave pretreatment. Food and Chemical Toxicology 32: 897-903.

Gross, G.A.; Grüter, A. (1992). Quantitation of mutagenic/carcinogenic heterocyclic aromatic amines in food products. Journal of Chromatog-raphy 592: 271-278.

Kazerouni, N.; Sinha, R.; Hsu, C.H.; Greenberg, A.; Rothman, N. (2001). Analysis of 200 food items for benzo[a]pyrene and estimation of its in-take in an epidemiologic study. Food and Chemical Toxicology 39(5): 423-436.

Knize, M.G.; Andresen, B.D.; Healy, S.K.; Shen, N.H.; Lewis, P.R.; Bjeldanes, L.F.; Hatch, F.T.; Felton, J.S. (1985). Effect of temperature, patty thickness and fat content on the production of mutagens in fried ground beef. Food and Chemical Toxicology 23: 1035-1040.

Larsson, B.K.; Sahlberg, G.P.; Eriksson, A.T.; Busk, L.A. (1983). Polycyclic Aromatic-Hydrocarbons in Grilled Food. Journal of Agricultural and Food Chemistry 31(4): 867-873.

Layton, D.W.; Bogen, K.T.; Knize, M.G.; Hatch, F.T.; Johnson, V.M.; Fel-ton, J.S. (1995). Cancer risk of heterocyclic amines in cooked foods: An analysis and implications for research. Carcinogenesis 16: 39-52.

Lijinsky, W. (1991). The formation and occurrence of polynuclear aromatic hydrocarbons associated with food. Mutat. Res. 259: 251-261.

Nadon, L.; Siemiatycki, J.; Dewar, R.; Krewski, D.; Gerin, M. (1995). Can-cer Risk Due to Occupational Exposure to Polycyclic Aromatic-Hydrocarbons. American Journal of Industrial Medicine 28(3): 303-324.

Ohgaki, H.; Takayama, S.; Sugumura, T. (1991). Carcinogenicities of het-erocyclic amines in cooked food. Mutation Research 259: 399-410.

Rivera, L.; Curto, M.J.C.; Pais, P.; Galceran, M.T.; Puignou, L. (1996). Solid-phase extraction for the selective isolation of polycyclic aromatic hydrocarbons, azaarenes and heterocyclic aromatic amines in char-coal-grilled meat. Journal of Chromatography A 731: 85-94.

Robbana-Baranat, S.; Rabache, M.; Rialland, E.; Fradlin, J. (1996). Hetero-cyclic amines: Occurrence and Prevention in Cooked Food. Environ-mental Health Perspectives 104: 280-288.

Salmon, C.S.; Knize, M.G.; Panteleakos, F.N.; Wu, R.; Nelson, D.O.; Fel-ton, J.S. (2000). Minimization of heterocyclic amines and thermal inac-tivation of Escherichia coli in fried ground beef. Journal of the National Cancer Institute 92: 1773-1778.

Shirai, T.; Sano, M.; Tamano, S.; Takahashi, S.; Hirose, T.; Futakuchi, M.; Hasegawa, R.; Imaida, K.; Matsumoto, K.-I.; Wakabayashi, K.; Sugi-mura, T.; Ito, N. (1997). The prostate: A target for carcinogenicity of 2-amino-1-methyl-6-imidazo[4,5-b]pyridine. Cancer Research 57: 195-198.

Sinha, R.; Chow, W.H.; Kulldorff, M.; Denobile, J.; Butler, J.; Garcia-Closas, M.; Weil, R.; Hoover, R.N.; Rothman, N. (1999). Well-done, grilled red meat increases the risk of colorectal adenomas. Cancer Re-search 59(17): 4320-4.

Skog, K.; Jägerstad, M. (1993). Incorporation of carbon atoms from glucose into the food mutagens MeIQx and 4,8-DiMeIQx using 14C-labelled glucose in a model system. Carcinogenesis 14: 2027-2031.

Skog, K.; Steineck, G.; Augustsson, K.; Jägerstad, M. (1995). Effect of cook-ing temperature on the formation of heterocyclic amines in fried meat products and pan residues. Carcinogenesis 16: 861-867.

Sugimura, T.; Nagao, M.;Kawachi, T.; Honda, M.; Yahagi, T.; Seino, Y.; Sato, S.; Matsukura, N.; Matsushima, T.; Shirai, A.; Sawamura, M.; Ma-tsumoto, H. (1977). Mutagen-carcinogens in foods with special refer-ence to highly mutagenic pyrolytic products in broiled foods. Origins of Human Cancer. H. H. Hiatt, J. D. Watson and J. A. Winsten. New York, Cold Spring Harbor: 1561-1577.

Vogelstein, B.; Kinzler, W.W. (1992). Carcinogens leave fingerprints. Na-ture 355: 209-210.

Wakabayashi, K.; Nagao, M.; Esumi, H.; Sugimura, T. (1992). Food-derived mutagens and carcinogens. Cancer Research (suppl.) 52: 2092s-2098s.

Ward, M.H.; Sonha, R.; Heineman, E.F.; Rothman, N.; Markin, R.; Weisenburger, D.D.; Correa, P.; Hoar Zahn, S. (1997). Risk of adeno-carcinoma of the stomach and esophagus with meat cooking method and doneness preference. International Journal of Cancer 71: 14-19.

Wynder, E.L.; Gori, G.B. (1977). Contribution of the environment to cancer incidence: an epidemiologic exercise. Journal of the National Cancer Institute 58: 825-832.

Zheng, W.; Gustafson, D.R.; Sinha, R.; Cerhan, J.R.; Moore, D.; Hong, C.-P.; Anderson, K.E.; Kushi, L.H.; Sellers, T.A.; Folsom, A.R. (1998). Well-done meat intake and the risk of breast cancer. Journal of the National Cancer Institute 90: 1724-1729.

Zimmerli, B.; Rhyn, P.; Zoller, O.; Schlatter, J. (2001). Occurrence of het-erocycic aromatic amines in the Swiss diet: analytical method, expo-sure estimation and risk assessment. Food Additives and Contaminants 18: 533-551.


M U S C L E B I O L O G Y

Use of Cloning and Transgenesis in Pigs

Randall S. Prather* & David E. Gerrard

Introduction A brochure from the breeding company contains a count-

less number of animals from which to select breeding stock. A caption below one of the ‘genetic prototypes’ reads “just feed Tender-Gro® 30 days prior to slaughter and we ‘guar-antee’ that animals fed this product will produce the most tender meat possible for your local packer, money back guarantee.” Another caption reads, “feed Gro-Fast® to those animals (males or females) destined for meat production and we guarantee faster weight gains and maximal returns when animals are sold on a grade and yield program.” Yet, another reads, this animal has been the top carcass animal “on the rail” for the last three years. Although the aforemen-tioned seem somewhat futuristic in principle, or perhaps impossible in the case of the latter, recent developments in biotechnology and genetic engineering make all scenarios possible in the near term.

The exact mechanisms controlling calpain activity in postmortem muscle are far from being “well-established,” yet many would argue that control of these proteases alone are key to making meat more tender in the future for con-sumers (Goll et al., 1998). Many have shown that during postmortem ageing, calpains attack and degrade proteins that are important for maintaining the organization and structure of muscle proteins (Koohmaraie et al., 2002). Once disrupted, muscle (meat) becomes more tender be-cause less force is required during the mastication process. What would it be worth to the meat industry for such a cru-cial protein to be present, and active, in higher than normal concentrations in the muscle of cattle at the time of slaugh-

ter? Is it even possible to deliver such proteases to the mus-cle? If so, the goal of providing consumers with consistently palatable meat is within grasp.

Regulation of growth, especially lean growth, is a com-plex mechanism that is likely controlled by a myriad of physiological parameters. One such physiological parame-ter that augments whole body growth is circulating levels of growth hormone (GH). When exogenous growth hormone is administered to lactating cows, milk production is greatly enhanced. Of course, this whole process has been exploited by agriculture and has been successfully commercialized for improving dairy herd production (Bauman et al., 1999). In other species, for example in pigs, the response is some-what different. In particular, daily administration of growth hormone not only improves growth rate but also acts as a “repartitioning agent” whereby nutrients are directed away from adipose tissue deposition and toward lean body mass growth (Thiel et al., 1993). As a result, altering circulating growth hormone levels is a very attractive means of improv-ing growth performance and productivity as well as lean composition. Unfortunately, the requirement for daily ad-ministration of GH is not, however, feasible nor is it practi-cal to many in the meat animal industries. Furthermore, there is substantial public resistance to using “injected hor-mones” as a means for improving animal productivity. Even though animal scientists must remain cognizant of public concerns, it is the obligation of those charged with improv-ing the efficiency of growing animals to remain vigilant and receptive to opportunities that may augment growth in a “consumer friendly manner.” This is clearly the benefit of using transgenesis and cloning. One such strategy currently being investigated rigorously to circumvent repetitive and constant delivery of growth hormone is to target “up-stream” regulators of growth hormone secretion somato-trophs from the anterior pituitary gland. In particular, scien-tists at Baylor have successfully expressed enough growth hormone releasing hormone (GHRH) in pig skeletal muscle to increase circulating insulin-like growth factor I concen-trations, which are “down-stream” of circulating growth hormone and elucidate peripheral tissue responses in the body (Draghia-Akli et al., 2002). Furthermore, these pigs grew at a faster rate than controls. Although this study was conducted using electroporation of DNA in skeletal muscle, these data show that the strategy of targeting growth hor-mone releasing hormone as a means to improve growth performance via the GH axis is possible and suggest that

R.S. Prather E125D ASRC, 920 East Campus Drive Department of Animal Sciences University of Missouri-Columbia Columbia, MO 65211-5300 [email protected] David Gerrard 202A Smith Hall Purdue University West Lafayette, IN 47907 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 83-87) June 15-18, 2003, Columbia, Missouri www.meatscience.org


this gene may be easy exploited using transgenic animal technologies.

Transgenic Animal Production A cursory perusal of the biomedical literature will quickly

reveal that transgenic animals, most notably transgenic mice, have contributed greatly to our understanding of how cells and organisms function. Both simple gene addition as well as gene removal has facilitated this addition to our knowledge base. The addition of genes permits questions to be answered about both gain of function and more recently reduction of function by knockdown experiments that use RNAi strategies (Tabara et al., 1998). One of the most im-portant additions to the biologist’s arsenal has been the abil-ity to knockout a gene (Smithies et al., 1985). In one em-bodiment, by using this strategy a stop codon is inserted into the coding region of a gene. When the ribosome trans-lates the resulting mRNA, the polypeptide is terminated and a shortened version of the protein is produced. If, for exam-ple, the production of the protein is terminated prior to the catalytic region of the mature polypeptide, then the function of that enzyme is knocked out. Alternatively, the gene can be altered to produce a modified protein, thus modifying function.

The actual knockout of a gene requires a technique enti-tled homologous recombination, and in mice, generally embryonic stem cells. A large number of embryonic stem (ES) cells can be used with either a conventional knockout strategy (both positive and negative selection) or by using a gene trap strategy. The specific recombination events are relatively rare (1 in every 1,000,000). The inefficiency of these techniques is not a problem because a large number of ES cells can be gathered to begin the project, and the ES cells can be maintained for a long period of time in vitro without undergoing differentiation or senescence. These two properties permit selection procedures that result in the survival of only those cells that have undergone the site-specific homologous recombination. These surviving cells can then be tested, and if appropriately modified, injected into the cavity of a mouse blastocyst. Inside the blastocyst, they form a chimera with the host inner cell mass cells of the blastocyst and result in a chimeric offspring. If some of these ES cells contribute to cells that form sperm or eggs, the genetic modification introduced by homologous recom-bination can be passed on to offspring, establishing that genetic modification in the mouse. To date, the establish-ment of functional embryonic stem cells that can form chi-meras and contribute to the germ line has only been shown in the mouse despite numerous attempts in other species (swine, ovine, bovine ) (Piedrahita, 2000, Wheeler, 2001).

Prior to December 2001, there were only a few methods described to make swine transgenic (Prather et al., 2003). These included injection of DNA directly into the pronu-cleus of a 1-cell stage embryo (Hammer et al., 1985), and sperm-mediated transfection via fertilization (Gandolfi et al., 1989, Sperandio et al., 1996). In December 2001, two addi-

tional methods were described, oocyte transduction (Cabot et al., 2001) and transduction of fetal-derived cells followed by cloning via nuclear transfer (Park et al., 2001). The major limitation of all these approaches for pigs is the lack of con-trol over how many copies of the gene integrate into the genome, as well as where those copies enter the genome. Thus investigators were limited to the addition of genes, and it was not possible to remove gene function.

Simple gene addition has been very useful in swine for both production agriculture and medical research. This topic was reviewed in 2000 at this meeting (Wells, 2000). Data was presented that show that pigs that incorporated a variety of transgenes (IGF-I, growth hormone) had in some cases increased growth rates and increases in lean muscle mass. In addition to altering meat quality and efficiency of production, the addition of genes has been very useful for things like the study of eye diseases. One group at North Carolina State University has created swine with mutated forms of rhodopsin (Blackmon et al., 2000; Petters et al., 1997). These animals manifest disease similar to human retinitis pigmentosa. Testing treatments in pigs has saved human patients from potentially harmful clinical trials. Also the possibility of xenotransplantation of swine organs into humans has been pursued by a variety of investigators who have added genes to modify complement hMCP (Diamond et al., 2001), hDAF (Cozzi et al., 1997), H2-DAF/beta actin-CD59 (Byrne et al., 1997, Levy et al., 2000)), and carbohy-drates by competitive inhibition (Costa et al., 1999) and blocking of Gal epitopes (Miyagawa et al., 2001).

Thus while the addition of genes has proved very useful, the technique has limitations. In some cases removal of a gene is necessary. For example, if one wanted to determine if myostatin knockout in swine would result in an increase in lean muscle mass it couldn’t be done by the random ad-dition of a gene. A technique to modify the coding se-quence of this gene such that a functional protein is not produced is necessary. In the example of xenotransplanta-tion, gene addition has resulted in prolonging the life of pig organ in nonhuman primates, but removal of a specific molecule on the cell surface is still required. In order to remove gene function in pigs, since there are no ES cells as in mice, it is necessary to perform homologous recombina-tion on the donor cells and then use those donor cells for nuclear transfer and cloning to create the animal (see be-low).

Knockout Swine In January 2002, we published a technique that resulted

in the removal of gene function (Lai et al., 2002). This tech-nique used a gene trap strategy on fetal-derived fibroblasts followed by cloning via nuclear transfer. The gene whose function was removed was alpha (1, 3) galactosyltransferase (GATT1). The galactose 1, 3 galactose sugar linkage pro-duced by this enzyme is thought to be responsible for hy-peracute rejection when pig organs are transferred into pri-mates (Auchincloss and Sachs, 1998, Cooper et al., 2002).


The only way to completely remove the function of this gene is to disrupt the coding region such that a functional enzyme cannot be produced. Two technologies came to-gether to enable the production of these knockout pigs: 1) a quick method of making the genetic modification, and 2) the ability to clone those genetically modified cells by trans-fer of the nuclei to enucleated oocytes. The gene trap strat-egy followed by quick selection was necessary because a stable cell line such as an ES cell line in pigs is not avail-able, and the fetal derived fibroblast cells senesce after about 30 population doublings. Thus isolation, homologous recombination (gene trap), selection, and expansion of those survivors had to occur rather quickly. If not performed quickly, the cells would senesce prior to use in the nuclear transfer procedures (Lai et al., 2002). The second technol-ogy that came of age is the same technology that produced Dolly the cloned sheep (Wilmut et al., 1997): cloning by nuclear transfer.

More recently, a second round of selection was per-formed on cells that had one copy of the GATT1 gene al-ready removed (Phelps et al., 2003). They discovered a sin-gle random point mutation that occurred in the reading frame of the other copy of the gene. These cells were ex-panded and used for nuclear transfer. Their domestic pigs now have both copies of the gene rendered non-functional. Similarly, we used our first GATT1 knockout gilt (NIH miniature pig) to derive fetal fibroblasts after nuclear trans-fer. We then added antibodies that recognize the galactose 1,3 galactose sugar linkage and compliment. Thirty-two clones were identified (~10-4) and one of these clones, after nuclear transfer and embryo transfer, resulted in a normal offspring (named Goldie) that did not have a functional copy of the GATT1. Neither human serum, baboon serum, nor IB4 lectin binds to the cells isolated from Goldie (Lai et al, in preparation). Thus she is an excellent candidate for the production of organs that might be transferred into hu-mans.

Swine as Models for Basic Research, Medicine and Agriculture

Genetically modified swine will have uses in both basic research as well as in production agriculture. In many cases the genetically modified mouse is not suitable for the stud-ies at hand. In discussions with researchers who work on mice with specific genetic modifications, the issue of size repeatedly arises. Mice, in many cases, are simply too small to take measurements (e.g. coronary artery blood flow for cardiovascular studies) or to practice treatments (bone splinting for osteogenesis imperfecta). Children born with osteogenesis imperfecta have weak bones and the treatment of choice is splinting to repair the broken bones. The mouse model exhibits the correct phenotype, but is simply too small to practice the splinting technique (Forlino and Marini, 2000). Similarly, a mutation in Fibrillin 1 results in humans that are subject to aneurisms and has resulted in the deaths of athletes (Kielty et al., 2002). Again, the knock-out mice exhibit the phenotype, but are too small to test

treatment strategies. Finally, retina transplants have been conducted in rats (Klassen et al., 2001), but even rat eyes are much smaller than human eyes and present challenges for developing treatment strategies.

In other instances, mice do not exhibit the expected phe-notype. In the case of cystic fibrosis the CFTR is mutated and results in the lack of chloride ion movement across the membrane. This gene has been mutated in mice, but there is no airway disease phenotype (Grubb and Gabriel, 1997), i.e. mice have a compensatory mechanism. Thus, even though the mouse is too small to test many of the mechani-cal treatments that are used for humans that have cystic fibrosis, it also has no symptoms of the disease. Thus a knockout of CFTR in another species such as the pig is war-ranted.

Large Offspring Syndrome A discussion of animals derived by nuclear transfer re-

quires a few words about abnormal phenotypes in offspring derived by this technology. Generally, these aberrant phe-notypes are referred to as Large Offspring Syndrome (LOS). LOS was first described in cattle that were derived from in vitro oocyte maturation, in vitro fertilization and culture prior to embryo transfer. The most prevalent phenotype is that of a skewed distribution of birth weights, with some of the offspring over twice the normal size (Walker et al., 1996, Wilson et al., 1995). The aberrant phenotypes are species specific: cattle show large birth weights and/or con-tracted tendons; mice show large placenta and/or obesity in old age; pigs show contracted tendons and/or respiratory problems. Fortunately, these phenotypes are not transmitted to the next generation (Tamashiro et al., 2002, Conway, 1996, Carter et al., 2002), as they appear to be a result of aberrant DNA methylation in the donor cell line or during early embryogenesis, and the DNA methylation pattern is erased and reestablished during gametogenesis (Humpherys et al., 2001, Rideout et al., 2001). Thus LOS is a manage-ment concern only in the first generation, as the aberrant phenotypes are apparently not passed on to the offspring.

Conclusion While we now have the technology in-hand to add genes

as well as remove genes, the procedures are not efficient. Technology that may be used in the near future to create pigs with specific genetic modifications is that of manipula-tion of the male germ cell prior to introduction into an ani-mal that has had its germ cells depleted (Brinster, 2002). It may be possible to perform homologous recombination on the germ cells prior to formation of the sperm. Transplanta-tion of these cells into a host may permit the production of genetically modified sperm cells. Then a male carrying these cells could be used to breed a large number of fe-males and the resulting offspring would carry the genetic modification.

As previously stated in the introduction, the potential ap-plication of genetic modification to meat science is enor-


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I N G R E D I E N T T E C H N O L O G Y

Microbial Problems, Causes, and Solutions in Meat and Poultry Processing Operations

Helen G. Brown

I will organize this paper around Poultry Raw, Beef Raw, and Fully Cooked Meat Products and for each will attempt to cover the Problems, Causes and Solutions.

Poultry Industry Problems

Salmonella is the primary microbial challenge for poultry. In 1997, USDA 9 CFR 381.94 established “Pathogen Re-duction Performance Standards” for Salmonella and E. coli. According to the standard, raw poultry product may not test positive at a rate exceeding the values of the CFR (1998); for broilers the standard is 20%. Salmonella is reported as inci-dence (% positive). Salmonella sampling is done by select-ing one WOG (without giblets, i.e. an eviscerated bird) and performing a WBCR (whole bird carcass rinse) with 400 ml of sterile solution.

Out of a 51 sample window, the maximum number of positives is 12. If a plant exceeds 12 positives of 52, the government writes an NR (noncompliance record) The NR states that the

“establishment shall take immediate action to meet the standard; when the establishment fails the (2nd) next FSIS 51 sample, reassessment of the HACCP plan occurs; and failure of the third con-secutive series of FSIS tests constitutes ‘failure to maintain sanitary conditions and adequate HACCP plan’…will cause FSIS to suspend inspec-tion services.. Until the establishment submits to FSIS written assurances detailing corrective action and measures to reduce the prevalence of patho-

gens.” [Ref. 9 CFR 381.94(b)(3)(I)]

Usually FSIS gives a plant the time to change their process before initiating a 2nd window (and luckily the Salmonella season can change during this time).

Although a plant gets a “heads up” call from USDA warning that they have 8 + during the sampling period, the NR is not issued until sampling is completed. In general, the FSIS will sample a plant for Salmonella once per year. A sample, one bird per shift/day, is pulled at a plant for 52 consecutive days. USDA Salmonella data is based solely on samples that the inspectors pull and send to their laborato-ries. I should also add that plants can and do “split” the USDA samples; hence, a call from USDA is not usually a surprise. Because of sampling problems, weekends, holi-days, temperature abuse during shipping, it is not uncom-mon for 70 or 80 samples to actually be pulled. Our com-pany has several years of historical data before and since the Salmonella standard went into effect. I would estimate that less than 10% of our 45 slaughter plants have ever failed one 52 day government sampling and none have failed the second window. Why don’t we fail 2 in a row? Because plants are very proactive in taking care of issues that cause NR’s.

The presence of Salmonella and generic E. coli are not re-lated. When I talk about E. coli and poultry I am talking about generic E. coli. It should be stressed that there has never been E. Coli O157 identified with poultry! Although there are relationships between fecal material and the level of E. coli (i.e. log values), the causes of high E. coli are basi-cally (UN-)sanitary equipment, (lack of) control of the evis-ceration process, (poor) control of fecal material and (in-adequate) levels of water and chlorine used to remove con-tamination. And, although there are two different govern-mental micro standards, it is rare that a plant has issues with E. coli because plants have developed strategies to control Salmonella and coincidentally improve their washing and chlorination processes!

In 1998, FSIS put forth a “Zero Tolerance” for fecal mate-rial. The Zero Tolerance is non negotiable and also part of HACCP plans. Water with and without chlorine is the “So-lution” to poor E. coli performance. Control of feed and water in the live birds is very important in controlling fecal contamination. The industry has learned a lot of manage-

Helen G. Brown, Ph.D. Tyson Foods, Inc. Food Safety and Research Laboratory 3609 Johnson Road Springdale, AR 72762 [email protected] Contents of this article Copyright 2003 by Tyson Foods, Inc., USA. All rights reserved. Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 89-93) June 15-18, 2003, Columbia, Missouri www.meatscience.org


ment tricks over the past five years while trying to conquer this problem. There are windows of opportunity for time off feed which impact consistency of fecal material and gut strength. Plants have gone to extremes of installing new evisceration equipment, changing and adding more bird wash cabinets, and in the process increasing number of gallons of water per bird. Plants prior to institution of zero fecal tolerance and the E. coli performance standard had water volume less than 5 gallons per bird. Some plants to-day use as much as 10 gallons per bird. (For calculation purposes, this is about 10 million gallons of water per week for an average poultry slaughter plant!)

Causes Chickens eat, sit, and walk where they poop. Fecal mate-

rial etc comes into processing plant in feather follicles. The scalding process, which is necessary to loosen feathers, can dissolve protective cuticle, enabling attachment of Salmo-nella. Bacteria are present on live birds; they go through hot (scalding) water to soften feathers to enable removing feath-ers. Scalder water is a “common water bath” and as such contains all the debris from the poultry house. After the birds are picked these, wet birds, have bacteria. During evisceration, birds drop onto common surfaces prior to be-ing re-hung for the evisceration process. In the “mechanical evisceration” process for poultry, the birds touch each other; they are warm (96+F) (doubling of bacteria occurs very quickly at this temperatures.) Additionally, cross-contamination or contamination by viscera can occur. Con-tamination can be bird to bird, or bird to equipment to bird. (One process that has been studied was to “superglue the guts” so they did not leak!)

When poultry has visible contamination (specifically fe-cal, feed materials) birds must be “reprocessed”. This origi-nally involved removal from the line and trim, trim, trim!). For several years now “On Line Reprocessing” (OLR) has been allowed by USDA. This process has three major parts:

• Wash to remove fecal, • Treat with antimicrobial, • Trim while on line.

Solutions Poultry is vertically integrated, where companies control

chicks, feed, management practices, yet most houses are actually owned by individual growers. There are one to ten houses per individual grower and the water comes from wells on the farm and the quality of water varies from grower to grower. In an attempt to control the amount of moisture that birds walk etc on, birds drink from “nipple” drinkers. Wet litter causes increased levels of fecal material in feather follicles and also changes the bacterial population on the birds. Litter beetles are a “vector” of Salmonella in chickens. Farmers in warm regions tend to have high levels of beetles and it is not surprising that farms with a high bee-tle population have bird health and feed conversion prob-lems.

Acetic acid, i.e. vinegar, and chlorine (household bleach) are frequently used in the drinking water to control bacteria.

USDA, ARS researchers at Texas A&M have looked at put-ting chemicals in the waterers to accomplish the same. Re-searchers at University of Georgia are using electrolyzed water and electrostatic spray of chemicals to im-prove/impact bacteria in the hatching process. One “solu-tion” is application of competitive microorganisms in live production. Companies, like Milk Specialties, Inc. (Pre-empt) and Calsporin, market Competitive Exclusion (CE) products that exclude the attachment of bacteria in the di-gestive tract. These are considered “drugs” by FDA. Most of these products are used in Japan and in some of the U.S. primary breeding operations. They consist of lactic acid bacteria that are applied by spraying the bacteria on eggs in the hatching cabinets. When the chicks hatch, they “preen” and consume the bacteria in the process. This sets up a di-gestive tract where Salmonella can not attach. Unfortu-nately, these products are expensive, two cents per chick; but the bacteria can cause “maturation” of the gut that justi-fies this high cost. (Faster maturation of the gut can result in improved animal performance and bird health.)

In the processing plant, Chlorine (sodium/calcium hy-pochlorite and gas) was historically the antimicrobial. With a “Zero Fecal” (tolerance) in place and USDA approval for OLR, several solutions have been added to the antimicro-bial arsenal. Below is a list of several “solutions” that are approved for OLR.

1. Rhodia-Avgard, TSP (Trisodium Phosphate) was the first approved “solution” for OLR TSP (and other OLR) solu-tions are applied by cabinet prior to water chilling the birds. TSP is used at 8-10% level, has 11-12 pH, and is very viscous. It acts in a detergent manner. This phos-phate-based chemical kills gram negative organisms. Some research has been suggested that Listeria tends to thrive because competing organisms have been de-stroyed. Over the years, there has been some debate as to a “Lazarus” effect of the TSP. Immediately after treatment (before the chiller) there are no Salmonella, yet after 1 hour in a cold water bath there may be 20% incidence Salmonella. So, obviously questions arise as to where the Salmonella comes from – hence the “rais-ing from the dead theory”! Poultry processors have ex-perienced some problems when using TSP: corrosivity, wear on metals etc, slick surfaces, plastics, rubber, and human skin pitting. Because of altering the disinfection properties of chlorine in the water (pH) in chillers and resulting environmental phosphate discharge issues, Rhodia is in process of developing AvGardXP SMS (So-dium Meta-silicate). Industry had expected approval by last fall (2002), but only a few poultry plants have switched to SMS Previously this compound has been used as a scalder additive in swine slaughter.

2. Alcide’s-Sanova (Acidified Sodium Chlorite), was the second solution approved for OLR. A 3 to 9 oz mist of up to 1200 ppm this chemical-citric acid and sodium chlorite originally was applied pre-chill in a vented cabinet. FDA amended food additive regulation to pro-vide for the safe use of acidified sodium chlorite solu-


tions as a component of a post-chill carcass spray or dip when applied to poultry meat, organs, or related parts or trim. Acidified sodium chlorite can now be ap-plied as a pre chill spray, a post chill spray or both and most recently as a pre chill dip.

3. Ecolab Inc. Inspexx is one of several products based on Peroxyacetic Acid chemistry that can be applied to hot or cold meat and poultry carcasses in spray cabinets and in chillers via spray chill systems (meat) or to parts, trim and organs. Another form, Vortexx, is approved for food contact surfaces and conveyor belts. Tsunami, a third form, is also used on vegetables. Peroxyacids are antimicrobial compounds for use on meat, poultry and food contact surfaces. They are “mixed” peroxyacids, i.e. containing more than one peroxyacid. Peroxyacetic acid is formed from the reaction of hydrogen peroxide with acetic acid. R = CH3 or a methyl group. This reac-tion is reversible. The secondary peroxyacid is octanoic acid, a saturated C-8 fatty acid, R=C7H15. With a mixed peroxyacid system, a much broader antibacterial spectrum is realized. Also, fatty acids will help wet out fatty surfaces such as meat and poultry surfaces.

4. Zep has introduced the ZAP’s process for OLR which uses chlorine dioxide in a vented cabinet. Chlorine di-oxide received approval several years ago for use in poultry chill waters, but gained more use on the turkey segment of the business than in chicken because of ex-posure time, concentrations, and off gassing of delivery systems. With this potent oxidizer (as with other chemi-cals) there is potential for the blood, visible through the skin in wing tips and blood vessels, becoming oxidized and browning. The Zep OLR process, which has “pilot” installations in 3 plants, because of the USDA validation requirements, has been very successful in re-ducing bacteria on poultry coming out of the water chillers

There are other chemicals seeking approval for use in OLR. Concerns about residual activity, leading to concern about toxicity and carcinogenicity of the product, must be satisfied prior to approval being granted for their use. Addi-tionally, systems must be designed, chemical concentra-tions validated and environmental concerns satisfied. Safe-Foods Inc. is pursuing approval for Cecure, CPC (cetyl pyridium chloride) for use in OLR .Zentox is looking at monochloramine disinfection. Chlorine chemical compa-nies are also looking for applications for their chemicals.

Beef Problems

The primary microbial problem to the beef industry is E. coli O157 H7. There are two types of interventions on beef: whole carcass interventions and “ingredients” used to re-duce microorganisms on beef trimmings and ground beef. There is no intervention that is a silver bullet; multiple hur-dles are put in place to reduce microbial loads and then products have to be cooked above a temperature that in-

sures bacterial kill. FSIS has determined that raw ground beef and other non-intact raw beef products are considered adulterated if found to contain E. coli O157:H7. The reason-ing was that raw ground products present significant public health risk because they are consumed after cooking that may not destroy E. coli O157:H7 organisms that can be introduced internally by chopping or grinding. Based on available data, FSIS believes that E. coli O157:H7 may be a food safety hazard reasonably likely to occur in beef pro-duction. Internal beef must be heated above 155 to destroy pathogens. . Although beef has been eaten raw and all the way to charred, poultry has never been eaten raw or even medium, rare. It is now illegal in most states to serve beef rare, especially ground or marinated products.

Causes Research has shown that bacterial attachment occurs the

first minute of bacterial contact with tissue surfaces. Thus it has not been difficult to draw a connection between fecal contamination from hides and viscera and E. coli O157:H7. As is poultry production, there is a large concentration of animals in a feed lot, they are at the mercy of weather and they eat where they poop also. Hence, physical removal of contamination is the primary means for controlling micro-bial E. coli O157:H7. Physical methods include trimming, and washing both of “areas and whole carcasses. Large feed lots and slaughter operation are washing live animals to remove contamination from the hides prior to them actually going into the slaughter plant.

Solutions I want to start by covering some of the hurdles put in

place in the slaughter plant and of unfolding interest on the trim. IBP Fresh Meats committed over $100 million to im-proved food safety and quality. This included development and implementation of food safety process that is trade-marked as Triple Clean™. This is actually a series of proc-esses that are strategically applied to every carcass. The processes include use of steam vacuums, carcass wash and organic rinse systems and steam pasteurization with a final organic acid rinse. This is very much a multiple hurdle “so-lution”.

In Step I of Triple Clean™knife trimming and hand held steam vacuums are used in the slaughter process to re-move/prevent contamination of the carcass by hide or in-ternal organs. Steam vacuums like spot carpet cleaners are used wherever contamination is found, immediately. Be-cause beef slaughter is not as automated and high speed, as poultry slaughter, the labor force is constantly cleaning up after every cut, etc. In Triple Clean™ Step II, after the hide is removed the carcass is completely washed followed by application of one of the USDA approved solutions (lactic or acetic acid). Because the wash is done so quickly after hide removal, bacteria have less time to attach and the an-timicrobial solution give an even greater kill for any bacte-ria left on the carcass surface. Step III Triple Clean™, after final USDA inspection the carcass goes through a high vol-ume low pressure “cabinet” to remove bone dust, blood etc. A 1-2 punch of steam pasteurization cabinet (where it is


blanketed with pressurized steam and a cold water rinse to cool this surface back down).

There are actually 5-6 ingredients considered safe and suitable along with radiation which are approved for appli-cation to beef carcass, parts, and trim. These are presented in the table below The Food and Drug Administration (FDA) and FSIS are working together on requests for approvals of ingredients and sources of radiation in a streamlined ap-proval process with simultaneous review of requests and petitions by FDA and FSIS. The attached table can be ac-cessed through the FSIS Labeling and Additives Policy web-site: www.fsis.usda.gov/oppde/larc Table 1. Ingredients considered safe and suitable for beef carcass, parts and trim.

Ingredient Reference Product Application

Lactoferrin

GRAS Notice (FDA Website)

Beef carcasses and parts

Direct food addi-tive

Peroxyacids 21 CFR 173.370 Beef carcasses

Secondary direct food addi-tive/Processing Aid

Acidified sodium chlorite

21 CFR 173.325

Carcasses, parts, and trimmings, as well as all processed, com-minuted or formed meat food products.


Ozone 21 CFR 173.368

All meat and poultry products


Sources of ionizing radiation

21 CFR 179.26

Pork, poultry, and beef products as listed.

Food additive

Secondary direct food additives are defined as “process-ing aids” by FDA definitions (not USDA) and the effects are “momentary,” with no residual effects. Hence the ingredient does not impact the label or standard of identity. Acids are good examples of processing aids; their functions are ap-proved (as acidulants, nutrients, antioxidants, etc). For use as an antimicrobial, the chemical companies have to submit data showing processing aid use and no residual impact on sensory characteristics (color or odor), or shelf life, or leave a detectable residual. If there is use according to labeling definition, the “solutions” actually become “ingredients” and hence need to be on the label. Although there have been other chemicals that are seeking approval, some products are not focusing on trim applications because of impact of acid on organoleptics: i.e. pigment! Mionix -Calcium Acid Sulfate and Sterifx are probably in this cate-gory.

Lactoferrin is one of the new generations of “solutions” for fighting bacteria. It provides protection against most ma-jor pathogens (E. coli, Listeria, Campylobacter, Salmonella, and Staph). Activated Lactoferrin (aLF) was granted GRAS status by FDA in October, 2001, and approval by USDA for use on beef in December, 2001. The use requires labeling “contains Lactoferrin, a naturally occurring dairy ingredi-ent”. There are two different applications a spray followed by rinse whereby bacteria are “detached” and “spray on

and leave on” for a “residual effect” This keeps down bacte-rial growth perhaps similar to CE. Terminus Lab Inc. (who had partnered with Farmland National Beef in the first use of this solution) is making application as a processing aid status for the detachment intervention. Information from Terminus Lab indicates that Lactoferrin protects up to 45 days when left on the beef, hence there is an extension of shelf life. One function of Lactoferrin is to absorb free iron that pathogens use and whether one in the same, it neutral-izes pathogens by eliminating attachment structures.

Peroxyacetic acid, the same product that is being used in OLR for Poultry, is approved for use as a red meat antim-icrobial. This is in the same family as the Inspexx used for on line reprocessing in poultry. In November, 2000, In-spexx 200 was approved by FDA (FR Vol. 65, No. 228, 70660-1). In February, 2001, commercial processing plant initiated Inspexx 200 as a pre-steam antimicrobial. Then, April 24, 2001 Excel established exclusive application. The peroxy acid has a double whammy antimicrobially speak-ing; it oxidizes and then has a lower the pH. It has been applied at a number of intervention points; before the evis-ceration cabinet, both pre and post pasteurization, after the hot water pasteurization, and in hot box applications. It has also been used on pork carcasses after the final wash, in hot box spray chilling and pre fabrication. Ecolab data has pre-sented data showing comparable cost to organic acids, and greater efficacy in reducing contamination. Currently, FDA approval is being sought for application to offal (head, tongue, etc.) and Meat Trimmings for Ground Beef.

Acidified sodium chlorite, (ASC) has been used both pre and post chill on beef carcasses. ASC has been used at 1000 ppm in a post skinning spray with significant reduc-tions for APC: 2.4 log reduction in APC VS .25 log reduc-tion with 2% Lactic acid. This reduction was attributed to the short attachment time in carcasses treated right after skinning. A 2-log reduction in APC was achieved when ASC was applied post chill: 4.4 log vs. 2.4 log (APC cfu/cm2 Data from Sanova 2003).

Ozone and Radiation are both approved as antimicrobi-als on beef. Ozone, which is a gas, can be solubilized in water for a millisecond and has been used in poultry chill waters. There are difficulties because of the short stability of the compound and because although a powerful oxidant, it oxidizes all organic matter including the fat, lean of the carcass, and shackles plus everything in the processing plant. Radiation of the whole carcass is very difficult to ac-complish, but frozen ground beef patties are currently being treated with low doses of radiation to kill bacteria. Although radiation must be labeled as an additive, the problems of public perception and cost have obviously been overcome for ground beef patties.

Fully Cooked Products Problems

I would be remiss if I did not cover microbial contamina-tion on fully cooked products and what can and is being


done to solve the problem of Listeria. Recalls are a pro-ducer/processors worst nightmare. When publicity sur-rounds one particular company and product (e.g. Minnesota firm recalls ground beef products for possible E. coli O157:h7 August 22, 2002), all the industry suffers. Stock prices can drop 10-20% reacting to huge recalls. And there have been companies who have ended up becoming part of larger companies because of (e.g. a 24 million pound) ground beef recall. The USDA FSIS has a web site where recall information is constantly updated. I went through the list of recalls for 2002 and through May 2003. In 2003 USDA recalls were split about evenly between Listeria and E. coli O157, and there were a couple of recalls for Salmo-nella on pork or beef (probably raw). In 2003, there were no recalls for micro on raw poultry. There have been 25 recalls of poultry and meat products this year: two for ground beef/beef trim for E. coli O157 and seven for Listeria poten-tially on fully cooked products. (One was chicken salad, 2 were pork products, and others were frankfurters, bologna, sausage.)

• Class I: A health hazard situation where there is a rea-sonable probability that the use of the product will cause serious, adverse health consequences or death.

• Class II: A health hazard situation where there is a re-mote probability of adverse health consequences from the use of the product.

• Class III: A situation where the use of the product will not cause adverse health consequences.

Listeria Recalls are Class I or II. In 2002 a USDA FSIS Positive Product Listeria Sample at Wampler Foods triggered the largest recall ever (27.4 million pounds of fresh and frozen ready-to-eat turkey and chicken products.) This led to increased Listeria testing at fully cooked processing plants as new regulations were promulgated. Purac has introduced PURASAL Lactic acid products that can be added to vac-uum packaged, uncured and cured meat products as a “natural antimicrobial”

Causes Listeria is an adulterant with zero tolerance. The problem

is very apparent the solutions are not quite so. Fully cooked product is sterile, but because Listeria grows in a damp en-vironment, sets up in niches, and forms biofilm that can not be removed during cleaning and sanitation, the environ-ment presents many opportunities for microbial contamina-tion during slicing, packaging, handling etc.

Solutions This spring USDA-FSIS proposed regulations that require

processing plants to have Listeria control programs in place. There are 3 methods a plant can use based on risk. What subsequently happens is that plants have to apply “solu-tions” to their problem or face extreme sampling, holding, and destruction, risk the NR’s and in general have potential of a lot of bad PR.

The risk assignment from lowest to highest are:

1. Apply post lethality treatment and antimicrobial or process to control LM.

2. Apply post lethality treatment or antimicrobial agent or process.

3. Does not apply post lethality treatment or agent or process so it has to have sanitation program, test food contact surface and hold when test is positive.

Listeria is heat and salt tolerant, and grows at cold tem-perature. Solutions for most micro are heat and sanitation. Unfortunately, this problem is not quite as simply fixed as it appears. Tyson Foods, Inc. has led the industry with a Trademarked “Listeria Sentinel Site” monitoring program. Contact and non contact surfaces are monitored daily for Listeria. Products are retained until results are negative and positive contact surfaces result in a swat team approach to finding exactly what causes the positive (e.g. maintenance personnel moving from raw to fully cooked areas, laying contaminated tools on a food contact belt etc.) The latest regulation defines the solutions based on risk. There have been a number of technologies introduced to prevent and control these problems. Post lethality treatments include radiant,(infra red), UV, heating, hot water, steam pasteuriza-tion, high pressure. Antimicrobial agents may be added to the product formulation, to the finished product or package. Antimicrobial processes include freezing, addition of lac-tates, acetates, diacetates, salt, nitrites, acid, or other addi-tives to drop the water activity.

Below is a table of Solutions for Fully Cooked Meat Products- specifically lactates and diacetates. Because of the above regulation much of the industry has undertaken to add lactates, acetates and diacetates to their fully cooked products. This reduces the risk level and sampling and pro-vides a comfort zone (because when Listeria is present dur-ing refrigerated shelf life there is no growth.) Purac has developed a tool to calculate levels of their/these products that will retard growth of LM in cured products that USDA actually cites: the Opti.Form Listeria Control Model. The effect of these antimicrobials is self evident (Source Bedie et al., 2001). No pathogen growth @ 70 days with 3% sodium acetate; 120 days @ 6%. 120 days no growth with .5P% sodium diacetate vs 50 days @.25P%. Sodium acetate is less effective but still inhibits Listeria growth as opposed to product with no Purasal. Table 2. Solutions for fully cooked meat products.

Antimicrobial Level (%) L. Monocytogenes Growth Inhibition

Sodium lactate 3 70 days no pathogen growth Sodium diace-tate

0.25 50 days no pathogen growth

Sodium acetate 0.25, 0.5

20 days no pathogen growth

Sodium lactate 6 120 days no growth and reduced pathogen growth

Sodium diace-tate

.5 120 days no growth and reduced pathogen growth

Control 0 Increased to 6 logs in 20 days


I N G R E D I E N T T E C H N O L O G Y

Natural Antioxidants Review

James E. Haworth

Introduction Antioxidants are substances that delay or inhibit the oxi-

dation of foods, and are therefore of great interest to food scientists. Antioxidants are naturally present in foods, but at very low levels. Therefore, additional quantities are added to control oxidation, increase shelf life, and improve overall quality. The mechanism by which this occurs is termed free radical termination, and is accomplished through the dona-tion of an electron or hydrogen atom. Antioxidants can also protect food by the deactivation of metal ions and singlet oxygen.

The most extensively used synthetic antioxidants in foods are butylated hydroxyanisole (BHA), butylated hydroxytolu-ene (BHT), Propyl Gallate (PG), and tert-butylhydroquinone (TBHQ). Due to the prooxidant effects of transition metal ions like magnesium, iron and copper, chelators are also used extensively in the food industry. Chelators such as citric acid (natural), ethylenediamintetraacetic acid (EDTA) and polyphosphates or their derivatives, are used to chelate metal ions. For many years there has been strong debate and concern regarding the safety of certain synthetic anti-oxidants as potential carcinogens. BHA, BHT, PG and TBHQ still remain on the GRAS (Generally Recognized As Safe) list, although limitations to their use have been im-plemented in the U.S., while BHT, PG and TBHQ still lack approval in many countries. Therefore, there is growing interest by consumers and the food industry in replacing currently used synthetic compounds with natural alterna-tives that are perceived to be safer and have wider con-sumer acceptance.

There are two main categories of antioxidants: primary and secondary. Primary antioxidants interrupt the free-radical chain of oxidative reactions by contributing hydro-gen from the phenolic hydroxyl groups, these forming stable free radicals that do not initiate or propagate further oxida-

tion of lipids. Secondary antioxidants trap radicals, chelate metals, regenerate primary antioxidants, or act as emulsify-ing agents. Synergism among different primary antioxidants, and between primary and secondary antioxidants is often taken advantage of in food products and should be consid-ered for all applications.

Market Since the 1980s, consumer interest in and demand for,

natural and organic products has increased, both in the U.S. and Europe. As a result, use of synthetic additives has de-clined while additives considered to be natural have grown, largely because the latter are perceived as safer. The natural trend, coupled with the growing market for premium food products, has driven the use of natural antioxidants like tocopherols (vitamin E), natural herbal flavorings, and ascorbic acid (vitamin C).

Many herbal extracts have antioxidant properties, and are therefore used as food antioxidants. The antioxidant func-tion can generally be linked to the presence of phenolic compounds such as rosmanol, carnosic acid, carnosol, and rosmarinic acid. The herbal extract most commonly used as a food antioxidant is rosemary (rosmarinus officinalis), which is native to most Mediterranean countries, and is now readily available throughout Europe (Frost and Sullivan et al., 2002). Although U.S. corporations lag behind the production capabilities of firms in the EU, some U.S. com-panies are growing rosemary in the southern states and in-creasing production capabilities.

Natural Antioxidants Natural antioxidants are commonly derived from plant

sources, and the efficacy is determined by plant species, variety, extraction and/or processing methods, and the growing environment. The mode of action for these sub-stances will vary depending upon the source material, the presence of synergists and antagonists, and of course the food matrix applied to.

In order to use any antioxidant preparation in food, it must be safe; easy to incorporate; effective at low concen-trations; possess no undesirable odor, flavor or color; be heat stable and have economic benefit. The possible effects of antagonists must be carefully considered since an anti-oxidant may become a prooxidant in the presence of cer-tain other molecules or at high concentrations. For exam-

J. E. Haworth, M.Sc. Senior Professional Cargill Health & Food Technologies 2500 Shadywood Road Excelsior, MN 55331 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 95-98) June 15-18, 2003, Columbia, Missouri www.meatscience.org


ple, chlorophylls may overwhelm the antioxidant effect of phenolics due to photosensitized oxidation and the pres-ence of transition metal ions. Metal ions, such as magne-sium, iron and copper, may render conditions favorable to oxidation.

Increased consumer demand for foodstuffs free from ad-ditives has lead to a growing interest in products that are perceived as natural. Herbal and tocopherol/vitamin E-based products, in particular, are recognized by consumers as being natural. Furthermore, regulations permit the label-ing of herbal extracts and/or tocopherols as natural, which is an appealing option to most food producers.

Herbals Herbal extracts and flavorings in commercial production

include rosemary, sage, and oregano, and are widely used in meat products. These substances contain varied but re-lated antioxidative compounds, including carnosol, car-nosic acid, rosmaridiphenol, rosmarinic acid, rosmanol and rosmariquinol. Extracts of rosemary, sage and oregano that have been deodorized and decolorized are now commer-cially available and their use in a variety of lipid-containing foods is increasing. Formulated herbal products are usually in liquid form, and are commonly added to meat products in the range of 500-5000 PPM (on a fat basis). The oleores-ins, which have GRAS status, have been used in various products such as potato chips, sauces, dressings, processed meat/poultry, and seafood as well as cakes and crackers. The antioxidant activities of such extracts/oleoresins maybe comparable to, or exceed, those of BHA and BHT, and are comparable to the efficacy of tocopherols depending on the quality of the extract. These herbal products have also found value by making the ingredient label more “nature friendly.”

Rosemary has been used for centuries in foods for flavor and protection from rancidity. Rosemary, and other herbal products, have been accepted in the food industry because of their “clean labeling,” a direct reaction to the public’s demand for all-natural foods. These products have tradi-tionally had limitations, including standardization of their antioxidant potency. Many factors, including climate, time of harvest, extraction process, and handling can affect the potency of herbal extracts. For example, a recent study ex-amined the relationship between carnosic acid levels in rosemary and its growing conditions. The growing condi-tions were, average hours of sunshine and average daily temperature per month. As seen in Figure 1, a direct rela-tionship was noted between the production of carnosic acid and the selected environmental conditions (Hildago et al., 1998). Many producers are now certifying their products on an activity basis vs. certifying specific levels of active chemicals.

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Figure 1. Relationship between carnosic acid level and rosemary growing environment.

It is generally recognized that carnosic acid has the high-est antioxidant potency of all the compounds found in rosemary extracts. As carnosic acid oxidizes, it “cascades” from one antioxidant to another, acting as a primary anti-oxidant throughout this “cascade,” and protecting the food system (RFI et al.). The phenomenon has been termed, the Carnosic Acid Cascade. When carnosic acid donates a hy-drogen to quench a free radical, it forms the antioxidant carnosol, which in turn forms another, rosmanol and so on. Carnosic acid thus has secondary and tertiary antioxidant formation mechanisms, although carnosol and rosmanol have only ~45% the potency of carnosic acid (RFI et al.). Many herbal extracts obtained from rosemary, sage, and oregano also contain hydrophilic antioxidants including compounds like rosmarinic acid that can act synergistically with the more lipophilic antioxidants. The blend of com-pounds is very important as it ensures a multi-phase food system will be broadly protected. Conversely, more lipo-philic antioxidants like tocopherols may be blended with natural emulsifiers like lecithin, which increases dispersabil-ity within a multi-phase system, and increase the effective-ness of the formulations. As seen in Figure 2, herbal prod-ucts can also take advantage of this emulsification effect (Haworth et al.)

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Figure 2. Emulsification effects on mixed tocopherols and a commer-cially available rosemary product.


Tocopherols and Tocotrienols Natural antioxidants may also be obtained from crude,

unrefined vegetable oils, including tocopherols and to-cotrienols. These substances are present as constituents of unsaponifiable matter, and may occur together with phos-pholipids, carotenoids, chlorophylls and triterpenyl alco-hols. Deodorization of these oils via molecular distillation yields a significant amount of purified tocopherols and to-cotrienols. Most of the global supply of tocopherols origi-nates from soybean oil processing, while tocotrienols are obtained from palm and rice bran oils.

Tocopherols and tocotrienols are monophenolic and lipophilic compounds. Tocopherols are the most widely used of these two compounds, and occur in four main forms termed alpha-, beta-, gamma-, and delta-tocopherol depending on the number and position of the methyl groups. In terms of vitamin E activity, d-alpha-tocopherol is the reference compound with the highest biological po-tency; however, in food systems, the order of activity is delta>gamma≥beta>>alpha. Tocopherols may be formu-lated as a 100% oil dispersible product, in dry form, or can be suspended/emulsified in water or brine solutions before inclusion into foods. Synergism between tocopherols and ascorbic acid or its derivatives has been well documented. Ternary mixtures of tocopherols, herbal extracts, lecithin or other phospholipids, chelators, and/or ascorbic acid or its derivatives exhibit excellent synergistic antioxidant activity in bulk oils, meat systems, and emulsified foods.

Antioxidant efficacy is determined by the suitability of antioxidants in each food system. In general, more hydro-philic antioxidants are better at stabilizing bulk oil than oil-in-water emulsions. The activity of lipophilic antioxidants follows the opposite trend (Frankel et al., 1998). There are many other parameters that must be taken into account when selecting antioxidants for food applications. Specific attention should be paid to the photosensitizing effect of chlorophylls in natural antioxidant products. In addition, the level of incorporation of antioxidants in foods should be optimized so that the antioxidant does not become a prooxidant at high levels. The use of chelating and emulsi-fying agents should also be considered.

Meats The most important reference to the consumer when

making a meat purchase decision is color. Consumers no-tice differences in color among meat products, and make purchase decisions based upon those differences. It has been estimated that up to 20% of all products are price re-duced, discarded, or reprocessed due to discoloration and consumer perceptions of the product being rancid (Sher-beck et al., 1995). Many retailers increase the overall price of all meat products to compensate for lost margin associ-ated with these problems.

Research has shown that natural antioxidants can im-prove the shelf life of meat products by delaying the onset

of oxidation. Several studies have revealed that high dietary levels of vitamin E can improve the shelf life of the meat products (Stubbs et al. 2002). Work has also been done showing direct addition of primary and secondary natural antioxidants to meat products can prolong shelf life and help preserve the color associated with fresh product. Fur-thermore, many studies have shown that best results may be obtained if a combination of these tactics is employed.

In beef, the red color associated with a fresh cut is caused when the meat surface becomes oxygenated. This is caused by the myoglobin undergoing a process called “blooming” in which the meat becomes fully oxygenated to the oxymyoglobin state. Oxymyoglobin continues to react with oxygen, or be broken down by photo oxidation, and further oxidizes to the metmyoglobin state. Once ~70% of the myoglobin becomes oxidized and forms metmyoglobin, the meat surface becomes discolored or brown as seen in Figure 3 (Boles et al.). Meat blooms after it is exposed to oxygen for 20-30 minutes, and will maintain this color for about 2-3 days when displayed in a retail environment. Using antioxidants may extend the oxymyoglobin state for an additional 1-2 days in a retail environment.

Figure 3. Interconversion of meat pigments.

Another important aspect of antioxidants is their role in the feeding regime of feed animals. Many studies have shown the effectiveness by feeding animals vitamin E in commercial feedlot settings. The effect of this administration of vitamin E has been enhanced flavor, color, and shelf life of the resulting meat products. Generally, synthetic vitamin E has been used to supplement feed animals on a commer-cial basis. Dr. Andreas Papas has shown that the natural d-alpha form is much more bioavailable in animals than the synthetic dl-alpha form. For example, it has been demon-strated that cattle absorb over 2.5 times more d-alpha than dl-alpha (Papas et al., 1991). Feedlots could realize the lar-ger benefits of increased bioavailability of the natural form, while only paying a slight premium for the product. At the same time, while many feedlots have been known to use vitamin E supplementation to increase product quality, new research has shown that herbal extracts could provide simi-


lar benefits. In a recent study published by the British Poul-try Science Journal, poultry diets were supplemented with either vitamin E, rosemary extract, or sage extract. Results with all three treatments showed a marked improvement in the shelf life of the uncooked refrigerated white meat sec-tions (Lopez-Bote et al., 1998).

Summary In conclusion, the main goal of incorporating natural an-

tioxidants into foods, specifically meats, is to increase prod-uct quality and overall appeal to consumers. Increasing the shelf life of meat products by incorporating natural antioxi-dants can be done in many ways including direct addition of primary and/or secondary antioxidants, bioavailability into the muscle via dietary administration, or combinations of the aforementioned. There is a growing consumer trend to seek natural ingredients, which bodes well for the use of natural antioxidants in foods for the years to come.

References Frankel, F. N. 1998. Lipid Oxidation Scotland: The Oily Press LTD.

Frost and Sullivan. 2002. European and United States Food Antioxidants Markets, Document #3952-88. Available for purchase from: http://www.frost.com.

Haworth, J.. 2003. Cargill, Inc. Internal data.

Hildago, P.J.; Ubera, J.L.; Tena, M.T.; Valcarcel, M. 1998. Determination of the Carnosic Acid Content in Wild and Cultivated Rosmarinus offici-nalis. Journal of Agricultural and Food Chemistry 46, p2624-2627

Boles, J. A.; Pegg, R.; Meat Color [Online]. Montana State University and Saskatchewan Food Product Innovation Program University of Sas-katchewan. Available from: http://animalrange.montana.edu/Docs/meat_color.htm. [Accessed 21 April 2003]

Lopez-Bote, C. J.; Gray, J. I.; Gomaa, E. A.; Flegal, C. J. 1998. Effect of dietary administration of oil extracts from rosemary and sage on lipid oxidation in broiler meat. British Poultry Science 39: 235–240

Papas, A. M., 1991. Vitamin E: Natural and Synthetic Forms are not Identi-cal. May/June

RFI Ingredients Inc.,. Functional Antioxidants/Antimicrobials/Natural Pre-servatives [Online]. Available at: http://www.rfiingredients.com/antioxidants.htm [Accessed 21 April 2003]

Sherbeck, J. A.; Wulf, D. M.; Morgan, J. B.; Tatum, J. D.; Smith, G. C.; Williams, S. N. 1995. Dietary supplementation of vitamin E to feedlot cattle affects beef retail display properties. Journal of Food Science 60(2), 250-2.

Stubbs, R. L.; Morgan, J. B.; Ray, F. K.; Dolezal, H. G. Effect of Supplemen-tal Vitamin E on the Color and Case-Life of Top Loin and Ground Chuck Patties in Modified Atmosphere Case-Ready Retail Packaging Systems. Meat Science (2002), 61, p1-5.


T E A C H I N G

Teaching Strategies for Preparing Students for the Meat Industry

Markus F. Miller

Introduction I believe we must ask ourselves what our students and

their employers are wanting when we determine teaching strategies for preparing students for the meat industry. Why do people attend a university? I would suppose there are many reasons one could derive that would explain why most students pay in excess of $150,000 to obtain a college degree. I would also pose the question, why do companies pursue and hire students with degrees from universities in-stead of hiring persons with other types of training? I believe that most people attend universities to obtain a degree in some field of study so that they will have the following ba-sic skills that were outlined by Dr. Gary Smith in his presen-tation “Preparing Undergraduate and Graduate Students To Meet Meat Industry Career Challenges”: (a) to think criti-cally, (b) to communicate effectively, (c) to lead decisively, (d) to decide independently, and (e) to compare logically and solve problems rationally. I believe in addition to these very important skills that we could add the following char-acteristics: (1) being self confident, (2) having the ability to work well as a team player, (3) performing well under pres-sure, (4) having a positive “can do” attitude, (5) having a high moral character and impeccable integrity, and (6) learning to pursue excellence.

I believe the ability of the instructors and students to de-velop and refine these characteristics prior to graduation will greatly impact their success after graduation. I will at-tempt to expand discussion on these characteristics and give possible strategies that may be used by instructors to prepare students to be successful after graduation.

(1) Being Self-Confident A recent survey of highly successful American women by

Focus on the Family indicated that more than 50% of them

listed lack of self-confidence and low self -esteem as the skills they lacked most. Employers want employees who are positive and believe in themselves. Students should always strive to maintain positive self-esteem. The important thing to understand is that self-confidence and high self-esteem must be earned. Students must deserve, and earn confi-dence through hard work; one cannot obtain it through arti-ficial success. Instructors must challenge students to push for excellence. Success will result in higher self-confidence levels. Success can be measured differently for each student based on his or her talent level, not by comparing against another person’s success or a numerical grade. Students must understand they do not have control over all circum-stances in their lives. However, students make the choice to succeed or fail. Instructors should strive to motivate students by giving challenging exams that require them to solve problems and learn through experience. A good work ethic leads to improved self-confidence. The satisfaction from hard work that results in success will always lead to higher self-confidence. The instructor should allow the student to succeed through hard work. Setting goals and achieving them leads to increased self-confidence. Goals are the indi-vidual steps we must take in pursuit of our dreams. Students should have big dreams. Students must understand that long-term success is a direct result of what they achieve everyday regardless of how small the improvement. Teach-ing strategies that allow for daily and weekly success will increase a student’s confidence and desire to perform well. Self-confidence is improved by the focus on specific goals and the achievement of those goals. Instructors should work with students to set goals and help them with the achieve-ment of their goals, which will lead to improved self-confidence. A big component of a successful attitude and improved self-confidence is to recognize weaknesses and confront them. Students should not set unrealistic goals. If their goals are too difficult, they will become counterpro-ductive. We are not always going to attain all of our goals, but the pursuit of them is a step in the right direction and will lead to improved self-confidence. The key is for instruc-tors to encourage students to fight through the tough times and self-doubt by reminding students that if we stay true to the course there will be a big payoff at the end. Instructors should always encourage students to remember to keep their vision of a better future. Attaining our goals will change our behavior. The change in our behavior, resulting

Markus F. Miller Department of Animal and Food Sciences Texas Tech University Box 42162 Lubbock, TX 79409-2162 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 99-101) June 15-18, 2003, Columbia, Missouri www.meatscience.org


from attaining our goals, will gradually lead to improved self-confidence.

(2) Be A Team Player Good communication skills are essential, and they start

with listening. Being a team player is a choice that can be made each day and it starts with respecting the other mem-bers of the team. While working in the industry, I noticed that employers never asked perspective employees if they could work well with people who were already on staff. I also noticed that rarely did perspective employees meet their future team members. Thus, it is imperative that stu-dents learn to work well with people who are very different from them. We must train our students to look for the good traits of others and not focus only on their obvious short-comings. The ability to interact with people on a daily basis is essential to long-term relationships and success. Students should avoid having to be right all the time. Students often make this mistake and in their desire to always be right, they inhibit constructive communication and prevent pro-ductive relationships from developing. Our goal is to com-municate better, not try to win every discussion or treat every conversation as if it is a contest with a winner and a loser. We must communicate both our needs and goals to other people so that everyone can benefit from our being a part of the team. People want to feel they are part of the process. We must train students to confront problems im-mediately, because if problems are not attended to and dealt with, they invariably get worse. Students usually avoid all conflict. They must learn to face conflict and communi-cate with the people they have problems with on various issues. Gossiping with others about problems instead of resolving the conflict face to face is a real problem. Students need to practice solving problems face to face with other team members while they are in college. In order to be a good team player, students must be trained to be humble, think of others’ needs first, treat others the way they want to be treated and be trustworthy. Students must be trained to listen to everyone regardless of their position or skill level. Respecting all members of the team is a choice that must be integrated into students prior to graduation.

(3) Work Well Under Pressure The ability to develop good habits, based on proper

techniques and mastered through the art of repetition so that they become second nature, will allow students to work well under pressure. The only way students can sys-tematically acquire good habits is by being organized. Be-ing organized will begin to put discipline into students’ lives. We must push students not to put things off. We must train students that it is impossible to be over prepared, es-pecially in today’s highly competitive marketplace. If stu-dents are committed to a career in the meat industry, then they must know everything they can possibly know about the meat industry. We must always operate on the axiom that knowledge is power. The more knowledge students have about the meat industry, the better students will per-form under pressure. Those who have been trained under adverse conditions will have the ability to perform well un-

der pressure. Students who struggle with their goals must differentiate between stress and pressure. Stress is the en-emy and robs us of our focus and inhibits our performance. Pressure is only negative if students allow it to affect their performance. Pressure did not affect us when we were chil-dren; we never thought about the things we weren’t going to be able to do. Students must recapture the mental state they had before the fear of failure lowered their confidence. All students have pressure points in their lives, so we must help them identify what they are and begin developing strategies to control them. Identifying what is causing the pressure is the first step, because if we don’t deal with the source, it will turn into stress and affect our performance. Pressure also can bring out extraordinary accomplishments. It pushes us harder. Apply the pressure, and your students can achieve anything. Students who are challenged men-tally, organized, and well-prepared will be able to handle the pressures they will face during their careers.

(4) Positive “Can Do” Attitude The reality is that we cannot control everything, but we

can control our attitude. We have the power to choose to be positive or negative. Unlike so many other things in life that we can’t change, we can control our behavior. Atti-tudes can be reversed. We can teach students to focus on the opportunities in solving problems. Looking at a situation positively enhances our quality of life and the lives of those around us. Positive, self-motivated people look at each day and each problem as a new opportunity. We can teach stu-dents to do this by conditioning them to look at things more positively, whether it’s unexpected change or the minor setbacks we all face in life. The key is to stay positive in tough times. The rule is simple: The more trying the times, the more positively we must reinforce our students. This is especially true in the workplace where industries and com-panies are going through challenges all the time. We must train students to look at change as a chance to be more successful. We must learn to maximize and focus on the good things and not allow students to focus on failures. Stu-dents need to be trained to view failure as an opportunity to learn how to be more successful. Some students are tough enough to power through life’s challenges with a seemingly unstoppable attitude; however, at one time or another we encounter an adversity that threatens our will to go on. The first type of adversity occurs when students experience a major failure that can leave them doubting themselves. We have to train students to step back and evaluate their role in the process. Why did the failure occur? Were their goals wrong, or was it their approach? Students have to examine their role in the failure and accept their share of the blame. Students must be trained to accept responsibility for their actions and to keep a positive attitude; it is a choice that leads to success. Students who can find solutions to the most difficult problems while keeping a positive attitude will be the most successful.

(5) Have High Integrity A high degree of honesty and morality is needed in to-

day’s employees. On the road to success, students are not


just learning from their experiences. People all around us can teach us many lessons if we would listen. The people we know and work with must be used as resources. The important thing is to select the right role models. Students should not look for people who make them feel good or friends who are always singing their praises. Students must learn from their mistakes and the mistakes of others. Some-times learning what not to do is more important than learn-ing what to do. We must teach our students to take advan-tage of the lessons learned by people who have made the journey before. The recent examples of the lack of corpo-rate integrity must be reinforced through our teaching of students. Students must be held to high standards and ex-pected to be honest. The response we instill in students when mistakes are made and failures occur will lead to higher levels of integrity. I believe students must be trained to make decisions based on what is the right decision. Stu-dents should not base their decisions on what they feel they can get away with because no one will find out. Honesty on exams, homework, and written assignments must be en-couraged and reinforced. True integrity is making the cor-rect decision when no one is watching. Students must make decisions they will be proud of in the present and future so that they can lead their peers by example through their ac-tions.

(6) Pursue Excellence The constant pursuit of excellence keeps students work-

ing at their full potential. Anyone can be great for a day, a week, and a month. The people who ultimately will be suc-cessful are the ones who understand that success is a long-term commitment, a marathon instead of a sprint. We must develop a “PHD” (Poor, hungry, and driven) attitude in our

students. An attitude of continuous improvement starts with the premise that we can always improve and become bet-ter. We must strive to help students understand that we are always going to face difficult times that challenge us. The key is to keep working, because the harder we work, the greater the result. We must train students to never quit and to never end the pursuit of their dreams. Students must de-velop an unstoppable attitude. Students must be challenged to find solutions to problems even when the solution is not easy to find. Abraham Lincoln failed at every level on his pursuit of the presidency of the United States. He never quit, never gave up, and kept pursuing his goals. During the most trying times he kept his focus. We must train students to keep clinging to their vision. We must train students to focus on their successes no matter how small and build on them. Students must always strive to be better today than yesterday and focus on being better tomorrow than today. A focus on getting the job done right the first, time no matter how difficult the task, will help students be the most suc-cessful.

We must train students to recognize that becoming suc-cessful is a process that never ends. The methods we use to become successful must always be a part of our life. Suc-cess comes with no guarantees: Today’s success is often tomorrow’s failure. A failure to teach students to maintain discipline and pursue excellence causes success to evapo-rate immediately. Teaching students only memorized mate-rial without a devotion to excellence will leave them un-prepared to face the challenges that face them after gradua-tion. “Pursuit of Excellence” is dedication to do a job that is hard to do, to go the extra mile when the easy way out is readily at hand.


T E A C H I N G

Teaching Strategies for Preparing Students for the Meat Industry

Tom R. Carr

Introduction The first ideal employee quality that Mark Franzreb iden-

tified in his presentation was “science is a given.” I am in-terpreting Mark’s quotation to mean that a Cryovac em-ployee must possess some fundamental/technical knowl-edge and skills related to meat science and food packaging. I think most of us here today would agree that the imparting of such knowledge and expertise is one of our major re-sponsibilities as institutions of higher learning. Meat science instruction has been around a long time, with many land grant institutions implementing introductory courses in the early 1900’s. Such Meat Science pioneers as Bull, Loeffel, Mackintosh, Kunkle, Ziegler, Francioni, and Bray initiated the instructional process.

At the University of Illinois, the original meat science fa-cility, including office and processing areas, was located in Davenport Hall and dedicated in 1901; the first meats course was taught in 1902. Much has changed since 1901 including facilities, students, instructors, and subject matter.

Typical/Traditional Courses I am going to take the liberty of characterizing the Uni-

versity of Illinois Meat Science/Muscle Biology academic program as somewhat traditional and therefore similar to many universities and colleges represented here this after-noon. I have listed those Meat Science/Muscle Biology courses that we offer at the University of Illinois:

ANSCI 100 Introduction to Animal Sciences

ANSCI 109 Meat Purchasing and Preparation

ANSCI 119 Meat Technology

ANSCI 209 Meat Animal and Carcass Evaluation

ANSCI 210 Meat Selection and Classification

ANSCI 309 Meat Science

ANSCI 409 Muscle Biology

Meat science is briefly discussed in our introductory animal sciences course, which all animal sciences freshmen are required to take during their first semester. This course generally involves four hours of lecture and a brief show and tell. Dr. Floyd McKeith teaches a service course (ANSCI 109) for those majoring in Hotel and Restaurant Manage-ment. We have undergraduate courses that address live evaluation, harvesting, fabrication and further processing of the three major red meat species. In addition, two graduate-level courses are offered that cover the fundamental bio-logical principles that influence growth, composition, proc-essing, preservation and meat quality along with the biosyn-thesis of muscle and connective tissue proteins. I assume that many of the institutions represented in this room today offer similar courses to their undergraduate and graduate students. The majority of our courses have laboratories and are certainly the most expensive courses taught, which cre-ates a major concern since our department does not have a teaching budget. Other courses that provide more knowl-edge and increased expertise are undergraduate research problems, field trips, and internships.

Student Outcomes What technical information and skills should our gradu-

ates possess? In reading the information that describes the AMSA Quiz Bowl, I was really intrigued by the list of topics that may be addressed in that competition. The topics listed were history of the meat industry, muscle structure and function, conversion of muscle to meat, food safety and HACCP, meat microbiology, meat grading, meat process-ing, meat industry and organizations, sensory evaluation, meat palatability, meat marketing and pricing, and others. I am certainly glad that I have matured to the point that I do not have to participate in such ego deflating activities. Cer-tainly, the University of Illinois would address some of these topics very effectively, while other areas would be covered rather superficially. I suspect most institutions would be in the same boat.

Tom R. Carr Professor University of Illinois 205B Meat Science 1503 South Maryland Drive Urbana, IL 61801 [email protected] Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference (pp. 103-104) June 15-18, 2003, Columbia, Missouri www.meatscience.org


In recent years, considerable pedagogical discussion has centered on such topics as “critical thinking, active learn-ing, problem solving, decision-making, study abroad ex-periences, learning teams, team building, and capstone ex-periences.” In 2001, approximately 20 percent of the Col-lege of ACES students at the University of Illinois had been involved in a study abroad experience, and that percentage will continue to increase. Many of our students have ex-perienced at least one internship by the time they graduate.

Dr. Gary Smith, in his Monday morning presentation, identified several ways in which students can develop criti-cal-thinking skills. Carefully designed laboratory exercises along with courses that emphasize live animal and product selection and evaluation certainly enhance critical thinking and decision-making skills. Students are often put into teams of three or four when harvesting and fabricating meat animals. These “hands on” courses assist in creating learn-ing teams as well as enhancing the team-building concept.

An excellent example of a capstone experience is the Na-tional Meat Animal Evaluation Contest. The Contest tests students’ skills and knowledge in the areas of market animal evaluation, breeding animal evaluation and carcass evalua-tion. In addition, students participate in a communications division and must answer questions on eleven different classes. It is truly a capstone experience in areas of live animal and carcass evaluation.

Educational Gaps Where do we fall short in preparing our students for a

dynamic meat industry? According to the National Associa-tion of Colleges and Employers, the following personal traits were identified as critical for a successful industry career: communication skills, honesty/integrity, teamwork skills, interpersonal skills, motivation/initiative, strong work ethic, analytical skills, flexibility/adaptability, computer skills, and organizational skills. Do we consider how we can improve a student’s teamwork, leadership, and communication skills as we prepare and organize that meat science course we have taught for ten years? How can we emphasize the importance of honesty and a strong work ethic in a traditional course setting: Some meat science graduates will begin their meat industry careers supervising plant personnel on a production line. Will they have the communication and interpersonal skills as well as the self-confidence to successfully meet their job responsibilities? How many students have had the opportunity to complete a labor/industrial relations course? The development of life skills will continue to challenge meat science/muscle biology faculty as we prepare students for the meat industry.

References JobWeb.com-Career development and job search help for college gradu-

ates. 2003. National Association of Colleges and Employers, 62 High-land Avenue, Bethlehem, PA 18017-9085.



Muscle & Lipid Biology

1st Place, Ph.D. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods FINISHING DIETS WITH ELEVATED LEVELS OF α-LINOLENIC ACID INCREASE FEED EFFICIENCY AND ADIPOSE LIPOGENESIS BUT DO NOT ALTER BEEF CARCASS QUALITY 1S. L. Archibeque, 1D. K. Lunt, 2R. K. Tume, 1S. B. Smith e-mail: [email protected] 1Texas A&M University, College Station, TX, 2Food Science Australia, Tingalpa D. C. Queensland, Australia Forty-five Angus steers (358 kg BW) were utilized in a com-pletely randomized block design with a 3 x 3 factorial ar-rangement of treatments to evaluate the hypothesis that dif-fering dietary α-linolenic acid (from corn, flaxseed plus corn, or milo) and whole cottonseed (WCS) inclusion (0, 5, or 15% DM) would interact to alter fatty acid metabolism and deposition of conjugated linoleic acid (CLA) in subcu-taneous (s.c.) and interfasicular (i.f.) adipose tissues, and thereby decrease carcass quality score. During the feeding period (135 d), steers receiving flaxseed or corn diets had a greater (P<0.01) gain:feed ratio (0.119 and 0.108, respec-tively) than steers receiving the milo diet (0.093). Following transportation to a local abattoir and overnight deprivation of food, there was less (P<0.01) decrease in weight in steers fed the flaxseed diet (1.51%) than in steers fed the corn (2.89%) or milo diets (3.11%). Marbling score was not af-fected by WCS (P= 0.14), nor was there a grain source × WCS interaction (P= 0.16). There was a grain source × WCS interaction (P<0.02) in that lean maturity decreased with increasing percentages of WCS for steers fed corn or milo diets, but was unchanged in steers fed flaxseed. Ribeye area of steers fed milo was less (P<0.01) than that of steers fed the corn or flaxseed diets. Lipogenesis from acetate in s.c. adipose tissue was greater (P<0.01) in steers fed flaxseed (5.42 nmol·h-1·105 cells-1) than in the corn (3.10 nmol·h-

1·105 cells-1) or milo (1.92 nmol·h-1·105 cells-1) groups. Stearoyl-CoA desaturase (SCD) activity in s.c. adipose tissue decreased (P<0.04) from 53 nmol·mg protein-1·7 min-1 in the 0% WCS group to 20 nmol·mg protein-1·7 min-1 in the 15% WCS group. The i.f. saturated fatty acid percentages increased (P<0.01) with increasing levels of WCS, and there was a tendency (P<0.09) for a similar effect in s.c. adipose tissue. The i.f. cis-9, trans-11 CLA percentage increased

with increasing WCS in the steers fed the corn diet, whereas it remained unchanged or even decreased slightly in the steers fed the flaxseed or milo-based diets (interaction, P<0.02). Steers fed flaxseed had a greater (P<0.01) s.c. adi-pose concentration of vaccenic acid (18:1 trans-11) than the steers fed milo and tended (P<0.07) to have greater amount of vaccenic acid than steers fed corn alone. Steers fed flax-seed also had greater (P<0.01) s.c. and i.f. percentages of α-linolenic acid (18:3, n-3) than steers fed either of the other grain sources. Steers fed flaxseed had the largest mean i.f. adipocyte volume (P<0.01), and s.c. adipocyte mean vol-ume tended to be larger (P<0.06). The increases in saturated fatty acids in s.c. adipose tissue appear to have been the result of the decreased SCD activity in s.c. adipose tissue with increased inclusion of WCS. Increased dietary α-linolenic acid from flaxseed may have increased s.c. adipo-cyte volume by stimulating lipogenesis. These data indicate that rations formulated to provide increased levels of α-linolenic acid (i.e., flaxseed) will increase feed efficiency and lipogenesis from acetate without altering either the quality or composition of the beef carcasses. Additionally, the inclusion of WCS in milo diets may cause a decrease in efficiency, less salable lean, and more saturated fat. Key Words: Steers, Adipose Metabolism, Linolenic Acid FATTY ACID PROFILES AND SENSORY PROPERTIES OF LONGISSIMUS DORSI, TRICEPS BRACHIL AND SEMIMEMBRANOSUS MUSCLES FROM HANWOO AND ANGUS BEEF S. H. Cho, J. H. Kim, B. Y. Park, Y. M. Yoo, I. H. Hwang, J. M. Lee e-mail: [email protected] National Livestock Research Institute Variation in fatty acid composition has an important effects on meat quality especially with the subcutaneous and in-termuscular (carcass fat) but also the intramuscular (mar-bling) fat. The aim of this study was to compare the fatty acid profiles for 3 muscles (Longissimus dorsi, LD, Triceps brachii, TB and Semimembranosus, SM) obtained from thirty-eight carcasses (18 steers of Hanwoo, 24 month old, 313-409kg carcass weight and 18 steers of Angus, 24 month, 342-423kg carcass weight) and assess their role in sensory perception. The following day of slaughter, the car-casses were boned and the LD, SM and TB removed, vac-uum packed, and aged at a 1C chiller for 7days to breaking into blocks for sensory evaluation and objective measure-ments including fatty acid analysis. The samples of each

P O S T E R S E S S I O N

Proceedings of the 56th American Meat Science Association Reciprocal Meat Conference June 15-18, 2003, Columbia, Missouri www.meatscience.org


carcass prepared with the same manner were frozen at -20C until analysis. The samples were cooked as both traditional grilled steaks (5 x 25mm) and Korean BBQ style (75x20x4mm). Sensory evaluation was performed for ten-derness, juiciness, flavor and overall liking on from 0 to 100 points continuous scoring line by 720 consumer panels for both cooking techniques. The consumer panels rated LD steaks and Korean style barbecue strips significantly more tender and more flavorsome than those from TB and SM muscles (p<0.05). Fatty acid profiles indicated some signifi-cant differences due to different muscles. Oleic acid (18: 1) was significantly higher (p<0.05) in TB as compared to LD and SM. The essential linoleic acid (C18:2) was significantly higher in TB and SM than LD(p<0.05). Proportions of other essential fatty acids, linolenic (C18:3) and arachidonic (C20:4), were not significantly different between TB and SM, but they were significantly higher than those of LD(p<0.05). For TB, the proportion of saturated fatty acids was significantly lower, while the proportion of unsaturated fatty acids was significantly higher than the other muscles (p<0.05). TB had a higher proportion of omega-3 and omega-6 polyunsaturated fatty acids than LD. For LD mus-cle, the proportion of saturated fatty acids was significantly highest, while the proportion of unsaturated fatty acids was lowest among three muscles (p<0.05). LD muscle had lower proportion of polyunsaturated fatty acids than the other muscles. From the sensory result of this study, LD muscles had significantly higher scores in flavor than the other mus-cles for both cooking methods. Fatty acid composition was related to eating quality, Beef flavor and overall likeness were positively correlated with saturated fatty acids, and negatively with polyunsaturated fatty acids. However, fur-ther research is needed to elucidate the relationship be-tween fatty acids profiles and flavor characteristics. Key Words: fatty acid composition, beef, sensory evaluation DEVELOPMENT OF A METHOD FOR ADIPOCYTIC DIFFERENTIATION FROM BOVINE ADIPOSE TISSUE FIBROBLASTS 1A. Gonzalez, 2A. Varela, 1A. Shimada, 1O. Mora e-mail: [email protected] 1Facultad de Estudios Superiores Cuautitlán,Universidad Nacional Autonoma de Mexico, 2Instituto de Neurobiologia-UNAM Understanding the molecular mechanisms and environ-mental cues that drive a somatic stem cell to become a preadipocyte and then to a mature adipocyte, might enable us to alter the growth of meat animals on a molecular level, and therefore to manipulate the ratio of muscle to fat in the carcass. With the aim of developing a serial subculture of fibroblasts from bovine adipose tissue and then try to differ-entiate them to adipocytes, two mediums were compared. Samples were taken from 3-4 years-old adults and from fetuses (in the last third of gestation). Animals were killed at the Querétaro City's municipal abattoir. Immediately after slaughter, samples of omental and subcutaneous adipose

tissue were collected from the adult animals; in the case of fetuses, samples were obtained from omental or kidney fat. The activity of Glycerol-3-phosphate dehydrogenase (G3PDH) was quantified as indicator cellular differentiation. In the case of adult cells, the serial subculture was estab-lished; however they could not be differentiated. As for the fetal adipose tissue, the serial subculture was established and cells from kidney fat were capable of differentiating when with the proper medium (DMEM/F-12 1:1; 10 µg/mL insulin; 0.25 µM dexametasone; 10 µg/mL very low density lipoproteins; 100 µg/mL streptomycin; 100 u/mL penicillin) was used. This was confirmed through the oil red O method. Based on the results it would appear that we were able to obtain a model that might be used to study the mo-lecular transcriptional mechanisms of differentiation from preadipocytes to mature adipocytes in bovine tissue. Supported by FES-C UNAM, Cátedra 5.12 and Consejo Nacional de Ciencia y Tecnología, Project J31295-B Key Words: Bovines, Fibroblasts, Adipocytes APPLICATION OF ACID SOLUBILIZATION ISOELECTRIC PRECIPITATION TO PORK PRODUCTS J.M. James, C.A. Mireles DeWitt e-mail: [email protected] Oklahoma State University, Stillwater, OK An evaluation of an alternative process has been investi-gated for its potential to improve low-valued red meat products. The acid solubilization isoelectric precipitation (SIP) method is used to obtain more functional protein con-centrate from low-valued meat products. The process takes advantage of differences in protein solubility to separate myofibrillar proteins from collagen, fat, and bone. Our pre-vious research established the applicability of using beef heart to extract proteins that have acceptable nutritional, compositional, and binding properties. However, more work was needed to determine if the process could be used with red meat from different species and on products that contained higher levels of fat and bone. The objective was to determine the composition and characteristics of pork heart (PH) and pork meat and bone meal (PMB) when utiliz-ing Acid-SIP. To obtain Acid-SIP proteins PH or PMB was blended 1:9 (w/v) with deionized water. The slurry pH was lowered to 2.5 to solubilize the myofibrillar proteins and centrifuged (3300 x g). The supernatant’s pH was raised to 5.5 to precipitate out the proteins and centrifuged again. Protein obtained from PH Acid-SIP and PMB Acid-SIP de-rived from the picnic shoulder were adjusted to 78% mois-ture and treated with or without 2% NaCl. Proximate analy-sis, cholesterol (AOAC 1995), and color using a Minolta CR-300 were evaluated for each raw treatment. The remain-ing protein from each treatment was stuffed into 21 mm cellulose casings and cooked in a 90ºC waterbath for 30 min. Proximate analysis, color, texture (TA-XT2i, Texture Tecnologies Corp, Scardale, NY) and water holding (WHA) and cook yield (Daum-Thunberg, Foegeding & Ball, 1992) were determined for each cooked treatment. The PMB


Acid-SIP extracted proteins had significantly less fat, choles-terol and ash than the original meat and bone meal. For Acid-SIP proteins from PH and PMB, the WHA (2.23±0.53 and 2.25±0.37g water/g protein, respectively) was compa-rable to comminuted meat batters from turkey (Daum-Thunberg et al, 1992). Cook yields were above 90% for both meat types after treatment with Acid-SIP. Texture Pro-file Analysis of the cooked links further demonstrated the gelling ability. Except for springiness, textural attributes of PMB with and without NaCl were not significantly different. Texture attributes of PH without salt were comparable to PMB, but PH with NaCl further enhanced the gelling ability. Based on results, utilizing Acid-SIP on PH and PMB im-proved nutritional composition and textural properties. Pro-teins obtained remained functional after extraction process so further work is needed to see if this method would have economic value when applied to mechanically separated meat and other byproducts. AOAC (1995). Official methods of analysis (15th ed.). Washington DC: Association of Offi-cial Analytical Chemistry.Daum-Thunberg, DL, Foegeding, EA, & Ball, HR. (1992). Rheological and water-holding properties of comminuted turkey breast and thigh: effects of pH. Journal Food Science, 57(2), 333-337. Key Words: Pork, Acid solubilization isoelectric precipita-tion, Functionality RELATIONSHIP BETWEEN µ-CALPAIN AUTOLYSIS AND IMMUNOLOCALIZATION IN PORK MYOFIBRILS 1Jamie Melody, 2Laura Rowe, 2Ted Huiatt, 2Steven Loner-gan, 2Elisabeth Huff-Lonergan e-mail: [email protected] 1PIC, USA, 2Iowa State University Degradation of myofibrillar/cytoskeletal proteins in post-mortem muscle plays an important role in the development of tenderness and water-holding capacity of pork. The cal-pain system degrades some of these key myofibril-lar/cytoskeletal proteins. One of the isoforms of the calpain enzymes, µ -calpain, has been implicated most often as the isoform likely to be responsible for many of the proteolytic changes observed in meat. Several factors influence calpain activity including free calcium concentration, inhibitor (cal-pastatin) activity, and autolysis. In living muscle, µ-calpain is considered a soluble, sarcoplasmic protein. In postmor-tem bovine muscle, immunoblotting has shown that µ-calpain becomes associated with myofibrils. This associa-tion increases as postmortem aging time progresses; how-ever, it is not clear whether µ-calpain precipitates non-specifically onto the myofibril or if it binds to certain re-gions of the myofibril. Therefore, the objective of this study was to examine the relationship between autolysis and lo-calization of µ-calpain in early postmortem myofibrils. Halothane negative Duroc pigs (n = 16) were harvested at the Iowa State University Meat Laboratory. Temperature and pH measurements of the psoas major muscle were taken at 0.5, 0.75, 1, 6, 12, and 24 hours postmortem. Muscle samples were collected from the left side of each

carcass at 0.75, 6, and 24 hours postmortem. Sarcoplasmic extracts were used for immunoblotting to determine the state of µ-calpain in the sarcoplasm at each time point (0.75, 6, and 24 hours postmortem). Highly purified myofi-brils were also obtained from samples at each time point. Myofibrils were used for immunoblotting to determine autolysis of myofibril-bound µ-calpain and for indirect im-munofluorescence to determine the localization of myofibril bound µ-calpain. In this study, it was noted that approxi-mately 94% of the psoas major samples at 45 minutes postmortem exhibited autolysis of µ-calpain in the sar-coplasmic fraction. By 6 hours postmortem, autolysis of µ-calpain had occurred in all samples. Immunoblotting of the myofibrils showed autolyzed µ-calpain was detected in pu-rified myofibrils as early as 45 minutes postmortem. In sam-ples with the most rapid pH decline, little µ-calpain was detected in the sarcoplasmic fraction at 6 and 24 hours postmortem. However, much immunoreactivity (as deter-mined by immunoblotting) for µ-calpain was found in the myofibril fraction at those same time points; suggesting that µ-calpain may have become associated with the myofibrils. To determine whether µ-calpain was binding to specific regions of the myofibril or was precipitating non-specifically onto the myofibril, indirect immunofluorescence using two different monoclonal antibodies against µ-calpain was used. Each antibody was specific to a different epitope of the 80-kDa subunit of µ-calpain. Both antibodies showed that µ-calpain appeared to bind specifically to the A-band and to the Z-line. Binding of µ-calpain to the myofibril was noted as early as 45 minutes postmortem in all psoas major mus-cles examined, supporting the results found using im-munoblotting. Therefore, this study suggests that µ-calpain does associate specifically with certain regions of the myo-fibril. Future studies are needed to address which proteins of the myofibril are involved in binding µ-calpain. Key Words: calpain, pork, myofibrils FETAL MUSCLE GROWTH AT DAY 78 AND 135 OF GESTATIONIN NUTRIENT RESTRICTED EWES M.M. Schwope, W.J. Means, A.W. Wolf, B.W. Hess, S.P. Ford e-mail: [email protected] University of Wyoming Laramie, WY USA Under-nutrition during early gestation can affect muscle growth in the postnatal lamb. Our purpose was to deter-mine if fetal muscle growth was affected by nutrient restric-tion of the gestating ewe. Nutrient restricted (NR) ewes were fed 50% of NRC recommendations during days 28 to 78 of gestation and 100% of NRC recommendations from 78 to 135 d. Control and NR ewes were euthanized (d 78 or d 135 gestation) prior to removal of gravid uteri. The head and internal organs were removed after the fetus(s) were taken from the uterus. Eviscerated ewes (pelt off) and fetuses were hung by the Achilles tendon for 24 to 34 h at 4ºC or 15ºC, respectively. Subsequently, ewe and fetus Longis-simus dorsi (Ld) and Semitendinosus (St) were removed.


Whole body, eviscerated body, Ld, and St weights were recorded. Differential fetal muscle growth was observed in d 78 fetal Ld muscle. Ld weight as percentage of fetal whole body weight and as percentage of fetal eviscerated body weight (EvBW) was higher (P= 0.05 and P= 0.05, respec-tively) in single fetuses from d 78 NR ewes compared to single fetuses from d 78 C ewes. These values, however, were similar in multiple fetuses from d 78 NR and C ewes. Fetal Ld weight, Ld as percentage of fetal whole body, and Ld as percentage of fetal EvBW did not differ between single or multiple fetuses from d 135 C and NR ewes. Nutrient restriction of ewes during 28 to 78 d of gestation caused differential changes in muscle growth of the fetus, but re-alimentation mitigated muscle growth differences between fetuses from NR and C ewes. Key Words: Fetus, Nutrient Restriction, Muscle Growth EFFECTS OF IMPLANT STRATEGY ON LIPID DEPOSITION IN FINISHED BEEF CATTLE K. R. Smith, S. K. Duckett, T. D. Pringle, M. J. Azain e-mail: [email protected] University of Georgia An experiment was conducted to determine the effects of implant regimen on carcass performance and quality, adi-pose cell diameter and subcutaneous (SQ) and intramuscu-lar (IM) lipid deposition of feedlot cattle. Ten Angus heifers (386 kg) sired by high marbling EPD bulls were randomly allotted to serve as controls (C) or implanted with Synovex-Plus (SP) at d 0 and 55. Real-time ultrasound measurements of ribeye area (UREA), fat thickness (UFT) and intramuscular lipid (UIMF) percentage were recorded at 28 d intervals throughout the finishing period. At 108 d, all heifers were harvested and SQ and IM tissue samples were collected for cell size and lipid composition determination. Data were analyzed using the GLM procedure of SAS with treatment, time and two-way interaction (when appropriate) in the model. Cellular data were analyzed with treatment, tissue and the two-way interaction in the model. Average daily gain was 36% greater (P <0.01) for SP than C. UREA in-creased (P <0.05) over time for both treatments; however, SP increased at a faster rate than C (0.31 vs 0.23 cm 2/d). UFT and UIMF increased (P <0.001) across time-on-feed but did not differ (P >0.05) between treatments. Implanta-tion altered (P <0.06) the magnitude of change in UIMF over time during finishing, with 82% of the total UIMF de-posited between d 27 to 55 in SP and 48% of the total UIMF deposited between d 55 to 80 in C. Final live weight and hot carcass weight were 11% greater (P <0.07) for SP than C. Ribeye area was larger (P <0.01) by 23% for SP than C. SP had 10% greater (P <0.05) overall maturity scores than C. Marbling score and quality grade were similar (P >0.05) between treatments. Total lipid and percentages of the major fatty acids in IM did not differ (P >0.05) between C and SP. Cell diameter distribution of adipocytes from SQ and IM were unchanged (P >0.05) between treatments; however, cell diameter differed (P <0.05) by adipose depot.

Use of anabolic implants in heifers with genetic potential to marble did not alter ultimate IM lipid content, size or com-position of longissimus; however, pattern of deposition was altered with implantation. Key Words: Beef, Implant, Marbling

3rd Place, Ph.D. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods ASSESSMENT OF POSTMORTEM POTENTIAL OF MITOCHONDRIA AND THEIR INTERACTION WITH MYOGLOBIN J. Tang, C. Faustman, S. Lee, T. A. Hoagland e-mail: [email protected] University of Connecticut, Storrs, CT USA Mitochondria (MT) and their respiration have the potential to decrease oxygen partial pressure and to change the bal-ance between antioxidants and pro-oxidants in postmortem muscle; these processes could influence the conversion of oxymyoglobin (OxyMb) to metmyoglobin (MetMb). The objective of this study was to assess the functional potential of MT isolated from bovine cardiac muscle and investigate the outcome of their interaction with myoglobin (Mb). States III oxygen consumption rates (OCR) and respiration control rate (RCR) of isolated MT from fresh bovine cardiac muscle decreased with decreased assay pH (7.2 � 6.4 � 5.6), and the effects were significant for state III OCR and RCR. When MT were isolated from cardiac muscle at 2, 24, 72, and 120 h postmortem, state III and IV OCR decreased with postmortem time at both pH 7.2 and 5.6; however, RCR and ADP/O (ratio of ADP to oxygen consumption dur-ing phosphorylation) decreased only when measured at pH 7.2 and no time effect was observed at pH 5.6. These re-sults indicate that MT still maintain some functional capac-ity in postmortem muscle and this is increasingly inhibited with decreased pH. Incubation of isolated MT with equine OxyMb and 6 mM succinate at pH 7.2 and 5.6 in a closed system caused decreased oxygen partial pressure, and de-oxymyoglobin (DeoMb) began to form when O2 decreased to 15% of its original concentration. MT respiration accel-erated equine MetMb formation when compared to controls at pH 5.6 in an open air system, while it increased DeoMb formation at pH 7.2. One possible explanation for these results is that MT respiration competes for oxygen, thereby favoring DeoMb formation; DeoMb oxidizes more readily at pH 5.6 than pH 7.2, and this could lead to greater MetMb formation at pH 5.6. Key Words: Mitochondria, Myoglobin, Oxygen consump-tion rate


Pre-Harvest Effects on Meat Quality

A COMPARISON OF CARCASS TRAITS AND PALATABILITY ATTRIBUTES OF CALF- AND YEARLING-FINISHED STEERS P. S. Brewer, C. R. Calkins, R. M. Rasby, T. J. Klopfenstein, R. V. Anderson e-mail: [email protected] University of Nebraska-Lincoln A two-year experiment was conducted to compare carcass characteristics and palatability attributes of steers (5/8 Brit-ish, 3/8 Continental) finished as calves or yearlings. Calves (n=74) were finished after weaning in the feedlot (191 d) on a high concentrate diet. Yearlings (n=83) grazed crop resi-dues after weaning followed by spring and summer pasture grazing and concluded with a short finishing period (91 d) in the feedlot. All steers were fed to a constant fat thickness endpoint of 1 cm. Steaks from each system were aged for 7, 14, or 21 d for Warner-Bratzler shear force (WBS) determi-nation and 7 or 14 d for consumer sensory evaluation. Calf-finished steers had lighter carcass weights, smaller longis-simus muscle areas, increased percentages of kidney, pel-vic, and heart fat, and higher marbling scores and USDA quality grades (P<0.05). Calf-finished steaks had lower WBS values, and higher sensory ratings for tenderness, juiciness, flavor, and overall desirability (P<0.05) than yearlings. Calf-finished steaks improved in sensory tenderness with aging while yearlings showed no improvement. Both groups had significantly lower (P<0.05) WBS values with each 7-day increment of aging from 7 to 21 d. These data indicate calf-finished steers have superior USDA quality grades, WBS values, and sensory ratings than yearlings. Key Words: Beef, Palatability, Finishing EFFECTS OF SUPPLEMENTING FISH OIL AND/OR CANOLA OIL ON ANIMAL PERFORMANCE, MEAT QUALITY AND FATTY ACID COMPOSITION IN BEEF CATTLE M.H. Gillis, S.K. Duckett, B. Jacob, K.R. Smith, C.E. Realini e-mail: [email protected] The University of Georgia, Athens Twenty-four Angus x Hereford steers (387 kg) were used to determine the effects of fish oil and/or canola oil supple-mentation in a finishing diet on animal performance, meat

quality and tissue fatty acid composition. Steers were ran-domly allotted to one of three diets: 1) basal high concen-trate diet (NONE; 88% concentrate, 12% grass hay), 2) basal diet plus 4% canola oil (CA), or 3) basal diet plus 3% canola oil and 1% crude fish oil (FISHCA). All steers were implanted with Synovex-S at the initiation of the study and fed the basal diet (NONE) for the first 41 d. After 41 d on feed, animals were gradually switched to treatment diets over a two-week period. From d 56 to harvest (d 106), all steers received their appropriate treatment rations. At 24 h postmortem, carcass data was collected, and samples were removed from each carcass for subsequent fatty acid, sen-sory, shear force and lipid oxidation analyses. Data were analyzed with dietary treatment in the model. Average daily gain tended (P = 0.07) to be greater for FISHCA than NONE or CA during the final 50 d on feed when treatment diets were fed. Hot carcass weight, dressing percentage, fat thickness, ribeye area or yield grade did not differ (P >0.05) between treatments. Marbling score and quality grade were higher (P <0.05) for CA and FISHCA than NONE. Lipid oxi-dation (TBARS, mg malonaldehyde/ kg sample) was greater (P <0.05) for FISHCA than CA or NONE, and TBARS values increased (P <0.05) over storage time in all treatments. Warner-Bratzler shear force (WBS) values tended (P = 0.06) to be higher for CA than FISHCA, with NONE being inter-mediate. Sensory panelist off-flavor scores were greater (P <0.05) for FISHCA ground beef compared to NONE or CA, which did not differ (P >0.05). Ground beef samples from steers fed NONE or FISHCA received higher (P <0.05) juici-ness and tenderness scores from sensory panelists compared to CA. Steaks from animals fed CA received higher (P <0.05) juiciness ratings by sensory panelists than NONE or FISHCA, which were similar (P >0.05). Initial and overall tenderness, beef flavor, and off-flavor ratings of steaks did not differ (P >0.05) by dietary treatment. Concentration of the cis-9, trans-11 CLA isomer was 30% higher (P <0.05) in ground beef from FISHCA than NONE or CA, which were similar (P >0.05). Concentrations of omega-3 fatty acids did not differ (P >0.05) by dietary treatment for ground beef. Feeding supplemental oils improved marbling score and quality grades. Feeding supplemental fish oil decreased WBS values in longissimus muscle samples. The addition of fish oil with canola oil to finishing cattle diets increased CLA concentration, lipid oxidation, and off-flavors in ground beef. Addition of fish oil with canola oil did not affect off-flavor ratings of steaks. Key Words: Fish Oil, Meat Quality, Beef




INFLUENCE OF LEVEL OF FLAXSEED ADDITION AND TIME FED FLAXSEED ON CARCASS CHARACTERISTICS, SENSORY PANEL EVALUATION, AND FATTY ACID CONTENT OF FRESH BEEF 1T. D. Maddock, 2V. L. Anderson, 1P. T. Berg, 3R. J. Mad-dock, 1M. J. Marchello e-mail: [email protected] 1North Dakota State University, 2Carrington Research Exten-sion Center, 3South Dakota State University To determine if the addition of flaxseed to cattle finishing diets influenced sensory properties and fatty acid composi-tion, specifically omega-3 fatty acids, ninety crossbred steers were randomly divided into six treatment groups. Treatments were: 1) control (corn-based diet), 2) a basal barley based diet, 3) 3% flaxseed + barley for 28 d, 4) 3% flaxseed + barley for 56 d, 5) 6% flaxseed + barley for 28 d, and 6) 6% flaxseed + barley for 56 d. Finished cattle were harvested at a commercial facility. No differences (P<0.05) were found among treatments for 12th rib fat thickness, REA, or marbling. Addition of flaxseed increased marbling score compared to the basal barley diet (P= 0.03). Boneless strip loins were removed from the carcass and a trained sensory panel evaluated the longissimus for palatability traits. Steers fed 6% flaxseed were rated tougher (P<0.05) than those fed 3% flaxseed. The control (corn) diet was rated juicier than all other treatments, but no differences (P>0.05) were found among treatments that included bar-ley. Flavor ratings were not affected by flaxseed addition (P>0.4). Samples from the longissimus were used for fatty acid content determination and were analyzed as a percent of total fat found in the muscle. Flaxseed inclusion in the barley diet increased (P<0.01) alpha-linolenic (18:3, n-3) fatty acid content. Six percent addition of flaxseed resulted in greater amounts of (P= 0.04) alpha-linolenic fatty acid than 3%, and steers fed flaxseed 56 d had higher (P<0.01) alpha-linolenic fatty acid content than steers fed flaxseed 28 d. Flaxseed addition did not change other measured fatty acid content (P>0.10). The inclusion of flaxseed into barley diets for finishing beef steers increased alpha-linolenic fatty acid content without significantly affecting flavor or carcass quality traits. Key Words: Flaxseed, Omega-3, Beef PREDICTION OF RETAIL YIELD IN GRASS-FINISHED BEEF 1,2E. Pavan, 1S. K. Duckett, 1H. R. Crowe e-mail: [email protected] 1University of Georgia, ADS, Athens, US, 2INTA-EEA Bal-carce, Balcarce, Arg. Thirteen Aberdeen Angus steers finished under similar graz-ing conditions were harvested and fabricated to establish the relationship between carcass traits (CT) and retail yield (RY) in grass-finished beef. After 12 h of fasting and imme-diately before slaughter, live weight (LW) was recorded. CT

were measured at 48 h postmortem and retail cuts were fabricated from one size after 7 day of aging at 4ºC. Mean, standard deviation (SD) and range of the principal variables are presented in the table. The correlation between all vari-ables was evaluated, and a stepwise regression analysis was performed to predict RY and the proportion of RY to hot carcass weight (RY:HCW) using all carcass variables. Yield grade (YG) was correlated to RC:HCW (p=.02, r=-.66). Al-though ribeye area (REA) was positively correlated to RY (p=.05, r=.56), its correlation with RC:HCW was lower (P=.10, r=.47) and with the quality grade (QG) was negative (P<.01, r=-.74). Thus, QG was negatively correlated to RY (P<.01, r=-.71) and to RY:HCW (P<.01, r=-.65). Fat thick-ness (FT) was correlated with LW and with HCW (P=.03, r=.60 and P=.02, r=.62), and tended to be correlated with RY (P=.08, r=.51), but no correlation was observed with RY:HCW (P=.18, r=-.19). RY was best estimated when HCW (87%) and REA (7%) were included in equation (RY = 7.08 + 0.45 * HCW + 0.44 * REA; p<.01; R 2= .93). When QG was included in the model, REA was replaced by QG, RY= 55.08 + 0.44 * HCW # 6.20 * QG (p<.01, R 2= .97), where HCW explained 86.8% of the variation in RY and QG 10.6%. The only variable that met the 0.15 significance level to enter in the model to estimate RY as proportion of HCW was YG (RY:HCW = 0.642 # 0.022 YG; P<0.01, R 2=.43). However, coefficient of determination increased to 0.81 (P<.01) when QG was included in the model, in this case RY:HCW was best explain by QG (43%) and LW (38%; RY:HCW = 0.8225 # 0.0242 * QG # 0.0004 * LW). In grass-finished beef the RY is mainly related to HCW and either REA or QG (marbling), although significant its contri-bution is low. The negative correlation between REA and QG may indicate that heavier muscled animals had lower QG when animals were finished on grass for similar age. In grass-fed beef, YG explained about 43% of the variation in RY:HCW; in contrast, equations using LW and QG ex-plained 81%. Variable Mean SD Range FT, mm 6.0 2.4 2.5-10.2 REA, cm 2 60.7 8.1 49.1-76.1 KPH,% 1.62 0.51 1.0-2.5 YG 2.52 0.59 1.80-3.80 QG 2.96 0.72 2.00-4.00 LW, kg 426.1 33.8 356.5-485.3 HCW, kg 255.8 24.0 213.9-300.3 DP, % 60.0 1.59 57.5-63.1 RY, kg 149.8 13.0 125.9-169.8 RY:HCW 0.586 0.020 0.559-0.636 Key Words: grass-finished beef, carcass traits, retail yield


2nd Place, Ph.D. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods EFFECT OF FORAGE VS. CONCENTRATE FEEDING WITH OR WITHOUT ANTIOXIDANTS ON CARCASS CHARACTERISTICS, FATTY ACID COMPOSITION, AND QUALITY OF URUGUAYAN BEEF 1C.E. Realini, 1S.K. Duckett, 2G.W. Brito, 2M. Dalla Rizza, 2D. De Mattos e-mail: [email protected] 1Animal and Dairy Science Department, The University of Georgia, Athens, 2National Institute of Agricultural Research Thirty Hereford steers were finished either on forage (FOR, n=10) or concentrate (CONC, n=20) to determine the effect of diet and antioxidants on carcass characteristics, fatty acid composition, and quality of Uruguayan beef. Half of the steers finished on CONC were supplemented with 1000 IU vitamin E/head/d (VITE). Postmortem vitamin C (VITC) was added to ground beef (1% w/v) displayed for 8 d. CONC carcasses had greater (P <0.05) carcass weight, conforma-tion, degree of finishing, fat depth, and ribeye area than FOR. FOR carcasses showed darker (P <0.05) longissimus color and yellower (P <0.05) fat than CONC. Initial Warner-Bratzler shear force (WBSF) values were similar (P >0.05) between FOR and CONC beef. However, FOR beef had lower (P <0.05) WBSF values at 7 and 14 d postmortem. Longissimus α-tocopherol levels were greater (P <0.01) for FOR and CONC-VITE compared to CONC. Ground beef from VITE had the lowest TBARS, while samples from FOR had numerically higher TBARS levels than other treatments. VITC treatment did not (P >0.05) reduce lipid oxidation. Steaks from FOR and VITE had similar (P >0.05) TBARS values, which were lower (P <0.05) than CONC during 21 d of display. VITE supplementation of CONC cattle had no effect (P >0.05) on color stability of ground beef or steaks. a* (redness) values were higher when VITC was added to ground beef. Longissimus fatty acid content of CONC was twofold greater (P <0.01) than FOR. The percentages of 14:0, 16:0, and 18:1 fatty acids were higher (P <0.01) in the intramuscular fat of CONC, while FOR showed greater (P <0.01) proportions of 18:0, 18:2, 18:3, 20:4, 20:5, and 22:5. Total conjugated linoleic acid (CLA) and CLA isomer c9t11 were higher (P <0.01) for FOR than CONC. VITE supplementation of CONC increased lipid stability of ground beef and steaks, but was unable to improve color stability; whereas VITC addition to ground beef increased color stability without altering lipid oxidation. Finishing cattle on forage enhanced the unsaturated fatty acid profile of intramuscular fat in beef including CLA and omega-3 fatty acids. Key Words: Beef, Forage, Antioxidants ENDOTOXIN-MEDIATED PINK COLOR DEFECT IN UNCURED, COOKED CHICKEN L. M. Sammel, J. R. Claus, M. E. Cook, M Yang e-mail: [email protected]

University of Wisconsin-Madison, Madison, WI During harvest, broilers may be exposed to high levels of E. coli endotoxin, which initiates an immune response and production of nitric oxide by activated macrophages. As a result, nitrite concentrations within broilers increase and may contribute to the undesirable pink cooked color spo-radically observed in breast meat. Therefore, the objective of this study was to determine if endotoxin exposure prior to harvest contributes to the cooked pink color defect in broiler breast meat. Thirty broilers (approximately 2.6 Kg live weight) were given an intraperitoneal injection of E. coli (O55:B5) endotoxin (1mg/Kg body weight) and served as treated birds whereas another thirty were sham injected to represent controls. Twenty broilers (10 control and 10 treated) were harvested 8, 12, and 16 hours post-injection. Birds were electrically stunned, bled, eviscerated, and sub-merged in ice water. After chilling 6 hours, the pectoralis major muscles were removed, vacuum packaged, and stored overnight at 2ºC. CIE L*a*b* values were determined on the lateral surface of raw breasts before samples were cooked to an internal temperature of 80ºC in water (85ºC). Samples were stored overnight prior to cooked color and pH measurements. CIE L*a*b* values and reflectance from 400-700nm were measured on two cross sections (2.54 cm thick) taken from the anterior area of each breast. Percent reflectance ratios to estimate nitrosylhemochrome (650nm/570nm) and nicotinamide hemochrome (537nm/553nm) were calculated. Raw breasts from treated birds harvested 12 and 16 hours after injection were darker (p<0.05) in color (lower L* values) than control birds. No differences in redness (a* values) or yellowness (b* values) were observed between treated and control raw breast samples. Cooked breasts were darker (p<0.05) in treated birds harvested 8 and 16 hours post-injection than controls and all breasts from treated birds were redder (p<0.05) than control breasts regardless of harvest time. No differences in yellowness for cooked breasts were observed between treated and control samples. Nitrosylhemochrome concen-trations were higher (p<0.05) in treated samples than con-trol samples regardless of harvest time. Treated samples from birds harvested 12 hours after injection had higher nicotinamide hemochrome concentrations than control samples and no differences were found in birds harvested 8 or 16 hours post-injection. Treated birds harvested 8 and 12 hours after injection had higher (p<0.05) pH values than control birds. These results indicate a potential new mecha-nism responsible for the pink color defect in uncured, cooked poultry. It appears that nitrite produced by live birds is contained in the muscle and may have adverse affects on cooked meat color. Further, birds exposed to the endotoxin had higher muscle pH than control birds that may have contributed to less pigment denaturation, and thus a pinker cooked color. Therefore, it is not only important to prevent nitrite contamination from an external source but also to control nitrite production within the live birds prior to har-vest. Reducing exposure of broilers to endotoxin may re-duce the occurrence of the pink color defect.


Key Words: Pink Defect, Endotoxin, Broilers EFFECTS OF BREED OF SIRE ON CARCASS COMPOSITION AND SENSORY TRAITS OF LAMB S. D. Shackelford, K. A. Leymaster, T. L. Wheeler, M. Koohmaraie e-mail: [email protected] USDA-ARS, Roman L. Hruska U.S. Meat Animal Research Center The present report includes results of the first year of a three-year-long experiment to evaluate effects of breed of sire on carcass composition and sensory traits of lamb. Dor-set, Texel, Rambouillet, Finnsheep, Romanov, Suffolk, Composite, Katahdin, and Dorper rams (5 per breed) were mated two a common breed of ewes and 270 offspring (ewes and wethers) were slaughtered serially and evaluated. Data were adjusted to a common slaughter age of 217 d. Carcasses of progeny of Suffolk sires were heavier (P <0.05) than those of the progeny of all other breeds except Dorper and Texel. Carcasses of progeny of Romanov sires were lighter (P <0.05) than those of the progeny of all other breeds except Finnsheep. Progeny of Finnsheep and Ro-manov sires had a higher (P <0.05) kidney-pelvic fat per-centage than progeny of all other breeds. Leg score was greater (P <0.05) for progeny of Texel sires than for those of all other breeds. Leg scores were lower (P <0.05) for prog-eny of Romanov sires than progeny of all other breeds ex-cept Katahdin and Finnsheep. Longissimus area was larger (P <0.05) for progeny of Texel and Suffolk sires than for those sired by all other breeds except Dorper. Longissimus area was smaller (P <0.05) for progeny of Romanov sires than for progeny of all other breeds except Dorset and Finn-sheep. Despite the diversity of breeds sampled, 12th rib fat thickness was only marginally (P <0.10) affected by breed of sire. Fat thickness at the 4th sacral vertebrae was greater (P <0.05) for progeny of Dorper sires than for progeny of all other breeds. Among the 270 carcasses sampled, whole-carcass ether-extractable fat percentage ranged from 18% to 40%. Breed of sire effected (P <0.05) carcass ether-extractable fat percentage with breed means ranging from 27.2% for Rambouillet to 31.3% for Dorper. The longis-simus of progeny of Finnsheep and Romanov sires con-tained a higher (P <0.05) percentage of intramuscular fat and received higher (P <0.05) marbling scores than that of the progeny of Rambouillet and Composite sires. Longis-simus chops from progeny of Finnsheep sires had the lowest slice shear force values (17.3 kg) and accordingly the high-est (P <0.05) trained sensory panel tenderness ratings (6.1). Longissimus chops from progeny of Composite sires had the highest slice shear force values (27.6 kg) and the lowest trained sensory panel tenderness ratings (5.2). Thus, it ap-pears that there are breed differences in lamb tenderness that could affect consumer satisfaction. However, no differ-ences among breeds were detected for lamb flavor intensity or off-flavor ratings. Although the level of difference be-tween breeds was quite small, longissimus chops from progeny of Finnsheep sires were more juicy than those of

progeny of Dorper, Rambouillet, and Texel sires. Finnsheep and Romanov, breeds known for having large litter size, share many common carcass composition and meat quality traits and produced the most tender loin eye muscle chops. Key Words: Lamb, Tenderness, Sensory THE INFLUENCE OF CREATINE AND A HIGH GLYCEMIC CARBOHYDRATE ON THE GROWTH PERFORMANCE AND MEAT QUALITY OF MARKET HOGS FED RACTOPAMINE HYDROCHLORIDE (PAYLEAN) 1C. A. Stahl, 1M. S. Carlson, 1D. L. McNamara, 1T. B. Schmidt, 1D. J. Newman, 2C. M. Schultz Kaster, 3T. A. Armstrong, 1E. P. Berg e-mail: [email protected] 1University of Missouri, 2Premium Standard Farms, 3Elanco Animal Health Crossbred barrows (n=128; 85kg) were blocked by weight and allotted to one of 16 pens (eight pigs/pen; four reps/treatment) using a completely randomized design. Treatments consisted of diets A (pelletted corn-soybean base formulated to meet or exceed all NRC requirements), B (diet A supplemented with 0.92% creatine monohydrate (CMH) and 2.75% dextrose), C (Diet B supplemented with 4.5 g/ton Paylean) and D (diet A supplemented with 4.5 g/ton Paylean). Animal weight and feed disappearance was recorded at 9d intervals throughout the 27d testing duration to determine ADG and feed efficiency. In addition, real-time ultrasound was used to establish 10th rib fat depth (FD) and loin muscle area (LMA) on d1 and 27. No treatment differences were noted when comparing ADG (P=0.66) and cold carcass weight (P=0.51). Over the 27d test, diets C and D expressed the greatest improvement in LMA growth (A: 6.84; B: 7.61; C: 9.35; D: 9.03 +/-0.58cm 2, P<0.01). Addi-tionally, diet affected d27 FD (A: 2.21; B: 1.90; C: 1.93; D: 1.85 +/- 0.08cm, P<0.05) and total fat accumulation (A: 0.69; B: 0.48; C: 0.46; D: 0.36 +/- 0.05cm, P<0.001). Moreover, boneless loin chops of animals fed diet C pos-sessed a greater percentage of intramuscular fat than ani-mals supplemented diet D (A: 2.43; B: 2.3; C: 2.45; D: 2.17 +/- 0.08%; P<0.07). Dietary treatment did not significantly affect the ultimate pH, Japanese color score or CIE L* and b*-values of the loin; however, the CIE a*-value of loins from animals fed diets B and D differed (A: 5.86; B: 6.49; C: 5.81; D: 5.20 +/- 0.23, P=0.0026) from those fed diets A and C. In conclusion, the addition of CMH and dextrose to diets containing 4.5 g/ton Paylean does not significantly improve growth performance; however, the data provide evidence that this dietary addition allows for the repartition-ing of nutrients without significantly altering intramuscular fat deposition. Key Words: Paylean, Creatine, Pigs


CARCASS, YIELD, AND PALATABILITY TRAITS OF STEER PROGENY OF HEREFORD, ANGUS, BRANGUS, BEEFMASTER, BONSMARA, AND ROMOSINUANO SIRES T. L. Wheeler, S. D. Shackelford, L. V. Cundiff, M. Kooh-maraie e-mail: [email protected] USDA, ARS, U.S. Meat Animal Research Center, Clay Cen-ter, NE In year one of two, carcass trait data were obtained for 270 steers resulting from artificial insemination matings of Here-ford (22), Angus (22), Brangus (21), Beefmaster (22), Bonsmara (19), and Romosinuano (20) sires to Angus and composite MARC III dams. For retail product yield and pal-atability traits, data were obtained for 260 wholesale ribs and 15 d postmortem longissimus thoracis steaks, respec-tively. Carcasses from Bonsmara- and Romosinuano-sired steers (329 and 323 kg, respectively) were lighter (P <0.05) than carcasses from other sire breeds (343 to 354 kg). A greater (P <0.05) percentage of carcasses from Angus-sired steers graded USDA Choice (75%) than carcasses from other sire breeds (27 to 45%). Adjusted fat thickness for carcasses from Angus- and Beefmaster-sired steers (1.1 cm) was greater (P <0.05) than for carcasses from Romosinuano-sired steers (0.8 cm). Longissimus area was greater (P <0.05) for carcasses from Brangus-, Bonsmara-, and Romosinuano-sired steers (86.5 cm 2) than for carcasses from Hereford-sired steers (81.9 cm 2). Carcass yield of boneless, totally trimmed retail product was lowest (P <0.05) for Angus-sired steers (61.4%), intermediate for Hereford-, Brangus-, and Beefmaster-sired steers (63.2, 63.4, and 63.2%, respec-tively), and highest (P <0.05) for Romosinuano- and Bonsmara-sired steers (65.6 and 64.4%, respectively). There were no differences (P >0.05) among sire breeds for weight of retail product. Longissimus from carcasses of Beefmaster- and Brangus-sired steers had higher (P <0.05) Warner-Bratzler shear force values (4.0 and 3.8 kg, respectively) than longissimus from Angus- and Bonsmara-sired steers (3.4 and 3.5 kg, respectively). Trained sensory panel ten-derness, juiciness, or beef flavor intensity ratings for longis-simus were not different (P >0.05) among the sire breeds. Relative to the British and American sire breeds, the Bonsmara and Romosinuano breeds appear to provide heat tolerance with no detriment to longissimus tenderness, im-proved retail product yield, and, thus, similar retail product weight despite a lighter carcass. Key Words: Beef, Breed, Quality


Post-Harvest Effects on Meat Quality

EFFECT OF HONEY ON COLOR AND LIPID STABILITY IN GROUND BEEF 1A.L. Alderton, 1C.L. Miano e-mail: [email protected] 1University of Kentucky Myoglobin and lipid oxidation are major causes of quality deterioration in fresh ground beef during storage. Honey is a complex natural liquid reported to contain a variety of antioxidants such as catalase, ascorbic acid, flavonoids and alkaloids. The use of honey to enhance color and lipid sta-bility would prove valuable to the beef industry given the current consumer trend towards natural antioxidants. Our objective was to investigate the antioxidant activity of light and dark honey and also to determine the ability of honey to delay lipid and myoglobin oxidation in ground beef stored at refrigeration temperatures. Light and dark honeys were obtained from a local distributor and analyzed for total antioxidant activity using an N,N-Diphenyl-N'-(2,4,6-trinitrophenyl)-hydrazyl (DPPH) colorimetric assay. Fresh beef chuck was obtained from Angus crossbred steers (n=6) and fine ground. Patties containing 1, 3 or 5% (by weight) light or dark honey were formed and stored fresh at 4°C. Control (CON) patties were formed with no added honey and stored under identical conditions. Hunter L*a*b* and thiobarbituric acid reactive substances (TBARS) analyses were performed on days 0, 1, 3, 5 and 7 of fresh storage. Total antioxidant activity (TOA) of dark honey was greater (P<0.05) than TOA of light honey as indicated by the DPPH colorimetric assay. TBARS values of patties containing ei-ther light or dark honey were lower (P<0.05) than CON following at least 5 days of refrigerated storage. In addition, the ability of honey to offset lipid oxidation increased with increasing honey concentrations. Finally, dark honey de-layed lipid oxidation more effectively that light honey as indicated by TBARS and supported by TOA. No differences in Hunter L*a*b* color values (P>0.05) were observed in ground beef with added honey relative to CON. The addi-tion of both light and dark honey to fresh ground beef at 1, 3 and 5% delayed lipid oxidation following at least five days of storage, but had no significant impact on meat color. Key Words: Ground Beef, Lipid Oxidation, Antioxidants

THE ROLE OF SUBCUTANEOUS FAT ON EATING SATISFACTION OF TOP LOIN BEEF STEAKS RELATIVE TO MARBLING CLASS Paul T. Berg, Martin J. Marchello, William D. Slanger e-mail: [email protected] North Dakota State University The objective of this study was to evaluate the role of sub-cutaneous fat (subQ) on the eating satisfaction of top loin beef steaks of 8 different marbling classes. Two short loins (NAMP #174) were selected by concensus of three trained evaluators for marbling classes PD, TR, SL, SM, MT, MD, SA and MA. Care was taken to ensure each loin was within the middle 20% of each marbling class ( i.e. SM 40 - 60). The short loins were aged 7 days in their vacuum bags at 1ºC. before being processed into 2.54cm boneless, centercut strip steaks (NAMP #1180A). Eight steaks were retained from each loin. SubQ fat was left on 4 steaks from each loin prior to cooking. Thus a total of 16 steaks from each mar-bling class was available for the taste panel. The steaks were randomly sorted, packaged in groups of 4 and labled to correspond to a specific table designation. A ''white table cloth'' restaraunt (its chef and serving staff) was rented and 128 adults were invited to participate as an untrained taste panel. The panelists were randomly seated at tables of 4 and a pre-identified package of 4 steaks was prepared for each table. Meals were standardized except for marbling class of the steak and whether the steak was flame broiled with the fat on or off. The steaks broiled with fat on had subQ fat removed prior to serving the guest. There were no duplicate treatments among the guests seated at any table to minimize verbal comparison influence. Panelists were asked to evaluate steaks for juiciness (J), flavor (FL), tender-ness (T), residual connective tissue (CT) and overall accept-ability (AC) using the AMSA 8 point hedonic scale. Except for J (P = 0.012), no significant differences were associated with marbling class although there was a tendency for pan-elists to rank steaks of greater marbling higher for T, FL and AC. The influence of marbling was greater for FL in fat on (P = 0.03) than fat off steaks (P = 0.94).Pvalues for T, CT and AC for influence of marbling by preparation method were greater than 0.05. The perception that J and T were related was apparent in fat on but not for fat off steaks (P = 0.0001 for fat on vsP= 0.29 for fat off). Similarly, the perception that J and CT were related producedPvalues of 0.001 and 0.82 for fat on and fat off steaks respectively. Key Words: Subcutaneous fat, Marbling class




IMPACT OF PORK QUALITY AND ENHANCEMENT ON THE SENSORY CHARACTERISTICS OF PORK. 1B.S. Bidner, 2D.S. Sutton, 1M.S. Brewer, 1T.R. Carr, 1M.E. Ellis, 1F.K. McKeith e-mail: [email protected] 1University of Illinois, 2Smithfield Packing Co., Smithfield VA Fresh pork loins (n=100) were selected to evaluate the im-pact of quality and enhancement on the palatability charac-teristics of pork. Loins were selected based on subjective color score of the longissimus blade end (A, B, C, D, for color score 1, 2, 3, and 4+, respectively, n=25 per group). Selected loins were divided into two equal sections, and randomly allocated to enhanced (brine solution containing sodium tripolyphosphate, potassium lactate, salt and natural flavorings) or control groups. Loin sections were vacuum packaged and aged 14d before chops (2.5 cm thick) were removed, vacuum packaged and frozen for Warner-Bratzler Shear force, and sensory analysis. Selection based on blade color score resulted in a wide range in fresh pork quality characteristics. Drip loss ranged from 0.1 to 7.0 %, Minolta L* ranged from 33.4 to 56.1 and glycolytic potential ranged from 28.5 to 158.4 µmole/g. Dramatic differences in pork quality existed between quality groups A and D for most traits measured. Group B and C loins did not differ for most meat quality traits except Minolta L*, subjective color score and subjective firmness score which reflected the color dif-ference that was apparent in the blade end. Aging for 14d resulted in higher Minolta L*, a* and b* values. Enhance-ment improved most fresh pork quality characteristics, which were evaluated after the14d-ageing period, as well as, improving palatability characteristics as evaluated by a six member trained panel. Cooking loss and shear force decreased, while sensory tenderness, juiciness and saltiness increased for enhanced verses non-enhanced pork. En-hancement, however, resulted in an increased incidence of visually apparent stripes in the cut surface of the loin. Sen-sory tenderness increased with quality group. A proportion of the variation in tenderness (R 2= 0.20 and 0.23) of en-hanced and non-enhanced pork, respectively, was ex-plained with ultimate pH using linear regression. These re-sults suggest that selection for high quality pork and en-hancement can impact palatability characteristics. Key Words: Pork , Quality, Palatability

THE EFFECTS OF FEEDING SUPRANUTRIONAL CONCENTRATIONS OF VITAMIN D3 TO FINISHING PIGS ON WARNER-BRATZLER SHEAR FORCE, SENSORY EVALUATION, COOKING LOSS, AND SHELF LIFE T.R. Bonner, C.R. Kerth, W.F. Owsley, W.R. Jones, L.T. Frobish e-mail: [email protected] uburn University, Auburn University, AL Yorkshire-cross pigs (n = 49) were assigned to one of five experimental finishing diets to determine the effects of high levels of vitamin D3 with or without phosphorus fed for 10 or 50 days prior to slaughter on meat quality traits. The diets were 1) a standard finishing (SF) diet which served as the control (CON); 2)a SF diet with 30,000 IU/kg supplemental vitamin D3 fed for 50 days prior to slaughter (50); 3) a SF diet with 30,000 IU/kg supplemental vitamin D3 fed for 10 days prior to slaughter (10); 4) a SF diet with 30,000 IU/kg supplemental vitamin D3 without supplemental phospho-rous fed for 50 day prior to slaughter (50-P); and 5) a SF diet with 30,000 IU/kg supplemental vitamin D3 without sup-plemental phosphorous fed for 10 days prior to slaughter (10-P). After 14 days of aging in a vacuum bag chops were frozen until they could be analyzed for Warner-Bratzler shear force (WBS) and by a trained sensory panel. Fresh chops were placed in a simulated retail setting for seven days and L *, a *, and b * values were taken with a Hunter Mini Scan to determine shelf life. Diet means were sepa-rated using orthogonal contrast and repeated measures for retail display were separated using Tukey#s multiple range analysis. WBS values for the 10-P diet were 1.07 kg higher when contrasted with those values from the 10 diet (P = 0.02). Cooking loss percentages for all animals fed diets containing supplemental vitamin D3 tended to be lower when contrasted with animals fed the CON diet (P = 0.07). Initial juiciness scores tended to be higher for chops from pigs fed the 10 diet when contrasted with those fed the 10-P diet (P = 0.09). Animals fed the 50 and 50-P diets tended to have higher sustained tenderness sensory scores when con-trasted with animals fed the 10 and 10-P diets (P = 0.09). Pork flavor intensity scores were higher for animals fed the 50 and 50-P diets when contrasted with animals fed the 10 and 10-P diets (P = 0.05). L *, a *, and b * values did not dif-fer for any diets at any day (P >0.05). These data indicate that feeding high levels of vitamin D3 and restricting phos-phorus may improve sensory evaluation. WBS values may increase when phosphorous is restricted in the diet. Cook-ing loss and shelf life were not improved by feeding these diets. Key Words: Swine, Pork Quality , Vitamin D


EFFECT OF AGING ON WARNER-BRATZLER SHEAR VALUES OF SELECTED MUSCLES FROM THE CHUCK AND ROUND 1C.L. Bratcher, 1D.D. Johnson, 2 B.L. Gwartney e-mail: [email protected] 1University of Florida, Gainesville, FL, 2National Cattle-men's Beef Association, Centennial, CO Studies from University of Florida and University of Ne-braska Scientists revealed that a significant number of mus-cles from the chuck and the round, when removed sepa-rately and cut across the grain, were very acceptable in sen-sory panel scores. Their conclusions were that there are numerous muscles that could be up-graded in value by cut-ting them into steaks rather than selling them as part of a roast or grinding into ground beef. The objective of this study was to determine the aging patterns of nine selected muscles from the chuck and round from two quality grades of beef. Two grades of cuts were studied: US Select and the upper 2/3 of the US Choice grade. The IMPS 115 2-piece chuck was separated and the following muscles were se-lected for study: infraspinatus, triceps brachii # lateral head, triceps brachii # long head, serratus ventralis, complexus, splenius, and rhomboideus. The IMPS 167A knuckle was also separated and the vastus lateralis and rectus femoris was evaluated. These nine muscles were selected because of the possibility that these could be used as steak cuts where tenderness is critical due to the probability that they would be cooked with a dry cooking method. All cuts were purchased from a major packer of known USDA grade and slaughter date. Each muscle was divided into four portions, progressing from anterior to posterior orientation to the car-cass, or from dorsal to ventral orientation to the carcass. One steak was removed from each portion of the muscle to be used for evaluation. Postmortem aging was conducted at 7, 14, 21, or 28 days, at 2±2ºC temperature cooler. After achieving their appropriate postmortem aging treatment Warner-Bratzler Shear force analysis were conducted on an Instron Universal Testing Machine. Eight of each subprimal for each grade was sampled and replicated twice. Postmor-tem aging affects all of the muscles evaluated in this study in a similar fashion. Therefore, consistent recommendations about postmortem aging can be given for these muscles. This study did find that USDA grade had an effect on post-mortem aging, in that muscles from the upper 2/3 of USDA Choice grade would not be necessary to hold beyond a seven day postmortem aging period. Muscles from lower marbled grades (i.e. USDA Select), should be aged a mini-mum of 14 days postmortem. Location within a muscle was found to have an effect on Warner-Bratzler shear values in four of the nine muscles evaluated. This would indicate that muscles would have to be treated on an individual basis when fabrication and merchandising individual retail cuts or portions from these muscles. For some muscles, location within the cut can be ignored and for others location must be considered for tenderness enhancement or product utili-zation. Key Words: Beef, Tenderness, Aging

COLOR TRAJECTORIES AS INDICATORS OF SPOILAGE IN FRESH MEAT 1R. S. Cusick, 2R. A. LaBudde e-mail: [email protected] 1Farmland Foods Inc., Wichita, Kansas, USA, 2Least Cost Formulations, Ltd., Virginia Beach, Virginia, USA Samples of fresh modified atmosphere packaged ground pork and beef were stored in a controlled environment and under controlled illumination. Each day sample packages were randomly selected and measured for color using two different measurement instrument systems. In addition, aerobic plate counts were determined and the samples sub-jectively evaluated for acceptable color. Statistically detect-able shifts in color were observed at the same approximate points in time (+/- 1 day) using all of the methods, with the usual microbial "index of spoilage" (>10 M CFU/g) corre-sponding to the breakpoint in color. Although multiple co-ordinate systems (RGB, CIE XYZ, CIE L*a*b*) or multiple criteria (R, rms difference, a*, Chroma, Cusick score a*-b*) provided acceptable detection of color shifts, examination of the color trajectories (i.e., b* vs. a* curves) for spoilage indicated a simple structure of apparent initial loss of chroma with near constant hue, followed by a strong devia-tion from the radial trajectory at the moment detectable spoilage occurred. Consequently spoilage is most easily detected using the single parameter (Cusick score) of a*-b* or by reporting the results in a new L* r* s* coordinate sys-tem obtained by rotating the a* b* axes by +45 degrees. Initial loss of color then occurs principally along the r* axis, with s* becoming non-zero at the point of spoilage. Key Words: Color, Spoilage, CIE COMPARISON OF THE ANTIOXIDANT EFFECTIVENESS OF CINNAMON AND GINGER IN COOKED GROUND BEEF Saumya Dwivedi, D. P. Cornforth e-mail: [email protected] Utah State University, Logan, Utah/USA The effects of cinnamon and ginger (0.1-1.0%) were tested as antioxidants in cooked ground beef, using the thiobarbi-turic acid (TBA) test. TBA values increased with time espe-cially in controls or samples with 0.1% spice. However, samples formulated with 0.5 or 1.0 % cinnamon or ginger had TBA values below 1.0 for 15 days at 2°C. Thus, both cinnamon and ginger had significant antioxidant effects. A usage level of 0.5% was optimum for both spices. Treat-ments with 1% spice were not different from treatments with 0.5% spice. Treatments with 0.5% cinnamon or ginger had lower TBA values (p<0.05) than treatments with 0.1% cinnamon or ginger. Key Words: Antioxidant, Cinnamon, Ginger


THE EFFECT OF HIGH POWER ULTRASOUND ON THERMAL TRANSITION AND SHEAR PROPERTIES OF POST RIGOR BEEF S.D. Jayasooriya, B. R. Bhandari, P. Torley, B. R. D'Arcy e-mail: [email protected] School of Land and Food sciences, University of Queen-sland, Queensland Australia Applications of high powder ultrasound to alter the physical and chemical properties of meat and meat products have attracted the interest of research workers for the past few decades. It is a pure physical technique which can be used as an alternative method in meat tenderization to chemical or thermal means of processing. In this research work, post rigor beef Semitendinosus and Longissimus dorsi muscle samples were subjected to ultrasonic treatment (24 kHz ultrasonic probe at an operational power output of 85 W cm -2) for 0, 30, 60, 120 and 240 seconds followed by 1, 3, 5 and 7 days of aging. The specific effect of high power ultrasound on pH, water holding capacity, thermal transi-tions, and Warner Bratzler shear values of the treated meat samples was investigated. Ultrasound treatment resulted in slight increase in pH and reduced the cooking losses. Dif-ferential scanning calorimetry revealed changes in endo-thermic transitions of myosin, collagen and actin. There was a decrease in objective shear force measurements, which indicated increase in tenderness of the treated specimens. Key Words: Beef, High power ultrasound , Tenderness USE OF HIGH AND LOW VOLTAGE ELECTRICAL STIMULATION STRATEGIES ENHANCE MUSCLE TENDERNESS AND COLOR FROM IMMATURE GOAT CARCASSES 1D. A. King, 1K. L. Voges, 1D. S. Hale, 2D. F. Waldron, 3C. A. Taylor, 1J. W. Savell e-mail: [email protected] 1Texas A&M University, College Station, TX, 2Texas Agricul-tural Experiment Station, San Angelo, TX, 3Texas Agricul-tural Experiment Station, Sonora, TX The production of immature, meat-type goats for cabrito has become a large market for goat producers in Texas. How-ever, consumer complaints regarding the tenderness and color of meat from these carcasses have been a concern. A study was conducted to examine the use of high and low voltage electrical stimulation in conjunction with postmor-tem storage to mitigate these problems. Boer cross (n = 60) kids were selected to be similar in weight and muscling and assigned to electrical stimulation treatments. The mean age and weight of the kids were 150 ± 5 d and 23 ± 2 kg, re-spectively. At approximately 45 min postmortem, the car-casses were electrically stimulated with 550 V (1.8 sec on, 1.8 sec off) for 2 min (HES), 20 V (2 sec on, 3 sec off) for 2 min (LES), or received no electrical stimulation. Muscle temperature and pH were monitored at 0, 2, 6, and 24 h after stimulation. At 24 h postmortem, carcasses were sepa-rated between the twelfth and thirteenth rib and at a point

immediately anterior to the aitch bone. The M. longissimus thoracis and M. gluteus medius were allowed to bloom for 15 min before L*, a*, and b* values were measured. Paired, short-cut, shank-off legs were vacuum packaged. One leg from each carcass was frozen immediately. The remaining legs from 42 carcasses were aged for 14 d to evaluate the effects of extended aging. In commercial practice, carcasses of this type are often frozen for shipment after 3 d. There-fore, the remaining legs from 18 carcasses were frozen on d 3. Warner-Bratzler shear force was determined on the M. biceps femoris of each leg. Statistical analysis was con-ducted separately on the Warner-Bratzler shear force for each aging time. All carcasses chilled rapidly with tempera-tures falling below 4º C within 6 h. No differences in tem-perature were observed between treatments at any time measured. Low voltage electrical stimulation had no effect on any variable measured. Carcasses receiving the HES treatment had a much faster pH decline than those from the LES or control treatments. Values for pH were lower (P 0.05) in the HES treated carcasses at 0, 2, and 6 h postmor-tem. Ultimate pH was not different between treatments. HES treated carcasses had higher (P 0.05) redness (a*) and yellowness (b*) values in the M. gluteus medius than LES or control carcasses. Additionally, M. longissimus thoracis from HES carcasses tended (P 0.1) to have higher L* and b* values than control carcasses. In legs aged for 1 or 14 d, the HES treatment tended (P = 0.09) to decrease Warner-Bratzler shear force values. Additionally, aging for 14 d im-proved (P 0.05) tenderness regardless of stimulation treat-ment. In the carcasses from which legs were aged for 1 or 3 d, Warner-Bratzler shear force values were lower (P 0.05) for muscles from HES treated carcasses than either of the other treatments. Aging for 3 d had no effect on the tender-ness of muscles regardless of stimulation treatment. These data indicate that high voltage electrical stimulation and extended aging were effective in improving the tenderness of meat from cabrito carcasses. However, aging for 3 d was inadequate to improve tenderness. Furthermore, high volt-age electrical stimulation made small improvements in the muscle color of these goats. Key Words: Goat, Tenderness, Electrical stimulation MUSCLE COLOR, PH, AND SHEAR FORCE RELATIONSHIPS AMONG EIGHT BEEF MUSCLES T.J. Koger, D.M. Wulf e-mail: [email protected] South Dakota State University One hundred beef carcasses were selected at three packing plants and used to determine muscle color, pH and shear force relationships among eight muscles. Individual muscles were excised from one hindquarter of each carcass at d-7 postmortem: longissimus lumborum (LL), psoas major (PM), gluteus medius (GM), tensor fasciae latae (TF), rectus femo-ris (RF), semimembranosus (SM), biceps femoris (BF), and semitendinosus (ST). Ultimate pH and colorimeter readings were measured on freshly-cut surfaces following a 90-min


bloom time for all eight muscles at d-7 postmortem. Sam-ples were frozen at d-7 postmortem and later thawed and cooked to 70ºC for Warner-Bratzler shear force determina-tion. Coefficients of determination (r 2) were calculated us-ing linear regression for inter-muscle relationships and quadratic regression for intra-muscle relationships. Coeffi-cients of determination (r 2) for using LL L* to predict L* readings of other muscles were significant (P<0.05) for GM (0.71), ST (0.70), SM (0.65), TF (0.41), RF (0.34), PM (0.30), and BF (0.24). Coefficients of determination (r 2) for using LL ph to predict pH readings of other muscles were significant (P<0.05) for GM (0.58), ST (0.49), SM (0.42), BF (0.13), PM (0.09), RF (0.05), and TF (0.04). Coefficients of determina-tion (r 2) for individual muscles for using LL shear force to predict shear force values of other muscles were significant (P<0.05) for RF (0.27), GM (0.22), SM (0.19), ST (0.15), BF (0.13), and TF (0.09). Coefficients of determination (R 2), calculated separately for each muscle, for using pH and pH 2 to predict shear force were significant (P<0.05) for SM (0.26), GM (0.25, LL (0.11), and ST (0.08). When dark cut-ters (n = 11) were excluded from analysis, the relationship between pH and shear force was generally weaker (R 2 = 0.11 for SM, 0.10 for GM, 0.04 for LL, 0.07 for ST). Coeffi-cients of determination (R 2), calculated separately for each muscle, for using L* and L* 2 to predict shear force were significant (P<0.05) for LL (0.20), SM (0.14), GM (0.12), TF (0.09), and RF (0.08). When dark cutters (n = 11) were ex-cluded from the analysis the relationship between L* and shear force changed only slightly (R 2 = 0.17 for LL, 0.10 for TF and RF, and 0.09 for SM). For BF and PM, the relation-ships of shear force with pH and shear force with L* were not significant (P<0.05). In general, color, pH, and shear force of LL exhibited weak to moderate relationships to color, pH, and shear force of the other muscles. Within muscles, shear force was related to color and pH of SM, GM, and LL. Key Words: pH, Muscle differences, Tenderness

3rd Place, M.S. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods EVALUATING CONSUMER ACCEPTABILITY AND WILLINGNESS TO PAY FOR VARIOUS BEEF CHUCK MUSCLES A. C. Kukowski, R. J. Maddock, S. W. Fausti, G. L. Taylor, D. M. Wulf e-mail: [email protected] South Dakota State University In-home consumer steak evaluations, followed by central-ized laboratory setting auctions (n = 74 consumers) were used to determine consumer acceptability and willingness to pay for various beef chuck muscles. Four muscles from the beef chuck: the infraspinatus (IF), serratus ventralis (SV), supraspinatus (SS), and the triceps brachii (TB), and the longissimus (LD) from the rib were evaluated, with the LD used as a reference to determine price and trait differentials.

Muscles from USDA Choice boneless boxed beef subpri-mals were aged 14 days, frozen, and cut into 2.5-cm-thick steaks. Consumers received two of each type of steak for in-home evaluations of uncooked steak appearance traits and cooked steak palatability. After in-home evaluation of steaks, consumers participated in a random-nth-price auc-tion session to determine willingness to pay for those steaks. Muscles differed for overall like of appearance (P<.05) with the LD, TB, and SS rated similar and highest, and the SV lowest. Like of shape, size, and leanness differed among muscles (P<.05) with the LD and TB rated similar and high-est for like of shape, and the SV the lowest; the LD rated highest for like of size, the SS and SV similar and lowest; the LD rated highest for like of leanness, the SV lowest. Palat-ability traits differed among muscles (P<.05) with the LD rated highest for overall like, and the SS and SV similar and lowest; the LD and IF rated similar and highest for tender-ness, the SS and SV similar and lowest; the LD and IF rated similar and highest for juiciness, and the SS lowest; the LD and IF rated similar and highest for flavor, and the SV and SS similar and lowest. Weighted-average price per pound (determined using binding price for each auction round; n = 35) was $4.38, $4.23, $3.78, $2.82, and $1.96 for the LD, IF, TB, SS and the SV, respectively. Average price differen-tials (determined using all bid prices for each auction round; n = 370) differed significantly from the LD and were $-0.71, $-0.79, $-1.75, and $-2.44 per pound for the TB, IF, SS and SV, respectively. Average price differentials were not different between the TB and IF (P>.05). Average price dif-ferentials for the SS and SV were different from the TB and IF and each other (P<.05). Average appearance trait differ-entials were significantly correlated to average price differ-entials; for the IF, like of shape had the highest correlation (r = .28); for the TB like of leanness had the highest correla-tion (r = .52); for the SS overall like of appearance was the only significant contributor of appearance traits for average price differential (r = .29); for the SV like of size had the highest correlation (r = .46). Average palatability trait differ-entials were significantly correlated to average price differ-ential; for the IF overall like had the highest correlation (r = .39); for the TB juiciness had the highest correlation (r = .45); for the SS tenderness had the highest correlation (r = .41); for the SV overall like had the highest correlation (r = .44). Demand analysis showed demand decreased by 2.60%, 2.44%, 2.09%, 1.96%, and 1.59% for every 1.00% increase in price for the SS, TB, LD, IF, and SV respectively. These data indicate the IF and TB were acceptable to con-sumers as steaks, however at prices lower than the LD. Key Words: Beef, Consumer, Willingness-to-pay


EFFECTS OF POSTMORTEM TIME AND STORAGE AND DISPLAY TEMPERATURES ON DEPTH OF OXYGENATION AND COLOR ATTRIBUTES OF BEEF LONGISSIMUS LUMBORUM AND PSOAS MAJOR MUSCLES AT 3 H BLOOM TIME R. Limsupavanich, D.H. Kropf, M.C. Hunt, E.A.E. Boyle, D.L. Boyle, T.M. Loughin e-mail: [email protected] Kansas State University, Manhattan, KS The combined effects of postmortem time (PT; 3, 5, 10, or 14 d), storage temperature (ST; 0 or 4.4º C), and display temperature (DT; 0 or 3.3º C) on depth of pigment oxygena-tion and instrumental color of beef Longissimus lumborum (LL) and Psoas major (PM) muscle cubes were investigated at 3 h of bloom. For each of 4 replications, sixteen samples of LL or PM from the right side of USDA Select (n=48) and Choice (n=16), were stored in vacuum at 0 or 4.4º C. At each PT, LL or PM from each ST was cut into a cube and placed into an open-top, clear plexi-glass container (3.8-cm 3 for LL, 3.2-cm 3 for PM). Two sides of each muscle cube were placed tightly to the container wall to facilitate digital image photography of the oxygenated layer 3 h after cutting and displaying at 0 or 3.3º C. Instrumental color measure-ment (illuminant A/10º observer of CIE L*, a*, b*, and re-flectance spectral data) was performed on the top surface of each muscle cube, which had been covered with polyvinyl chloride film and exposed to air. Oxymyoglobin (OMb), deoxymyoglobin (DMb), and metmyoglobin (MMb) forma-tion on the muscle surfaces were quantified using K/S spec-tral data. Digital images were processed using Adobe Pho-toshop 5.0 software. The depth of the oxygenated layer was analyzed using the Scion Image software (National Institute of Health). LL had a deeper (3.45 mm, P<.05) oxygenated layer than PM (2.02 mm) and more (P<.05) OMb, but less (P<.05) MMb and DMb by surface reflectance measure-ment. However, least squares means for a* did not differ (P>.05) between the 2 muscles. LL had greater (P<.05) L*, b*, saturation index (SI), %R630 - %R580, and hue angle values, but less (P<.05) a*/b* and %R630 -%R580 than the PM cubes. Muscles stored 14 d had greater (P<.05) L*, a*, b*, and %R630 - %R580 than 3 or 5 d, but did not differ (P>.05) from those stored 10 d. Muscles stored 10 d had less (P<.05) MMb, greater (P<.05) a*, SI, and %R630 %R580 values than those from 3 or 5 d. Colder DT in-creased L* and %R630 - %R580 (P<.05), while colder ST increased (P<.05) %R630 %R580. ST at 4.4º C allowed deeper (2.78 mm, P=.05) oxygenated layer than 0º C (2.68 mm). All factors affected hue angle and a*/b* values. This study suggests that longer PT (10 or 14 d) improved bloom color attributes. The oxygenated layer depth at 3 h was re-lated to surface bloom color attributes of LL or PM. Key Words: Oxygenated Layer, Image Analysis, Beef Bloom Color

EFFECTS OF ENDPOINT TEMPERATURE, COOKING METHOD, AND QUALITY GRADE ON SHEAR FORCE OF BEEF LONGISSIMUS LUMBORUM, BICEPS FEMORIS, AND DEEP PECTORALIS MUSCLES E. Obuz, M.E. Dikeman, J.P. Grobbel, J.W. Stephens, T.M. Loughin e-mail: [email protected] Kansas State University Our objectives were to evaluate the effects of endpoint temperature, cooking method, and quality grade on War-ner-Bratzler shear force (WBSF) of three different beef mus-cles. Subprimals (loin, boneless strip loin, NAMP 180; out-side round, flat, NAMP 171B; brisket, deckle-off, boneless, NAMP 120) from USDA Select and Choice, Certified Angus Beef carcasses were purchased and divided into respective muscles. Muscles were vacuum packaged and held at 1ºC for 14 days and then frozen (-37ºC). Each frozen muscle was sawed into 2.54-cm thick steaks, vacuum packaged, and stored frozen until cooking. Steaks were randomized statistically in a split-split plot design to one of two cooking treatments: a Magikitch’n® electric belt grill at 93ºC, or a water bath at 93ºC; and one of nine endpoint temperatures: 40, 45, 50, 55, 60, 65, 70, 75, or 80ºC. Steaks were thawed at 4°C before cooking. The center temperatures of steaks were monitored using copper-constantan thermocouples. Cooked steaks were then refrigerated overnight at 1ºC. Six cores were removed parallel to the muscle fiber direction from each steak, and WBSF was measured using an In-stron® Universal testing machine. Water-bath cooking re-sulted in higher (P<0.0001) WBSF (3.20 kg) than belt-grill cooking (2.88 kg) for the longissimus lumborum (LL). The combination of Select quality grade and cooking to higher endpoint temperatures resulted in higher (P<0.05) WBSF for LL. Endpoint temperature was the only significant factor (P<0.05) for the biceps femoris (BF) with two distinct phases of tenderization/toughening occurring. Between 40 and 60ºC, WBSF decreased from 4.48 kg to 3.89 kg, whereas between 60 and 70ºC, WBSF increased from 3.89 kg to 4.53 kg for BF. Water-bath cooking resulted in higher (P=0.0001) deep pectoralis (DP) WBSF (7.25 kg) than belt-grill cooking (6.04 kg). Endpoint temperature significantly affected (P<0.0001) WBSF for DP, evidenced by a strong decline between 45 and 65ºC, irrespective of the cooking method. Then, there was an increasing trend in WBSF be-tween 65 and 80ºC. Endpoint temperature and cooking method were more important factors than quality grade for the WBSF of the three muscles studied, with quality grade being significant only for LL. In contrast to commonly ac-cepted literature, we did not observe a distinct toughening trend in WBSF between 40 and 50ºC for the LL, BF, or DP. However, we observed an increasing trend for WBSF for either LL, BF, and DP between 65 and 80ºC, but this in-creasing trend was not as steep as in previously reported research. Our results suggest that optimum tenderness for the LL occurs at 55ºC and optimum tenderness for the BF and DP occurs between 60 and 65ºC. Higher marbling pro-vides insurance for tenderness at higher endpoint tempera-


tures. More rapid conduction cooking on the Magikitch’n® belt grill results in lower WBSF than slower, convection, water-bath cooking. Key Words: Beef, Endpoint Temperature, Shear Force INFLUENCE OF MARINATION AND COOKING REGIME ON THE TENDERNESS OF BEEF AND BISON TOP ROUND ROASTS Z. Pietrasik, J.S. Dhanda, P.J. Shand, R.B. Pegg e-mail: [email protected] University of Saskatchewan, Saskatoon, SK, Canada Collagen is the dominant protein of connective tissue and is largely responsible for textural differences between muscles. During thermal processing the insoluble portion of collagen denatures but denaturation is dependant upon the tempera-ture employed. For this reason, an optimal temperature and rate of cooking are essential in achieving the desirable tex-ture for a particular muscle cut. The objective of this study was to determine the combined effect of marination and different cooking regimes on the cooking yield and palat-ability of bison and beef top round roasts. Semimembrano-sus (SM) muscles from beef and bison top rounds were in-jected with a marinade to achieve 20% extension by weight and 0.5% sodium chloride and 0.3% sodium tripolyphos-phate levels in the finished product. After injection, each muscle was divided into four equal sized roasts; these were steam-cooked in a smokehouse to a final internal tempera-ture of 71ºC using one of the following four cooking re-gimes: cooking at a constant temperature of 75ºC (control); similar to the control treatment except that roasts were held at an internal temperature of 50ºC for 45 minutes (H45) or for 90 minutes (H90); and for the final regime, roasts were cooked at 55ºC with a 5ºC increase in smokehouse tem-perature every hour (UP) until the required internal tem-perature was reached. Hydration properties (i.e., cooking yield, expressible moisture, purge during storage of vacuum packaged slices) and textural characteristics (i.e., shear force) of processed roasts were determined.Marination by injection helped to improve the yield and tenderness of beef and bison SM muscles. The cooking yield for injected sam-ples (78%) was significantly (P 0.05) higher compared to non-injected controls (68%). When comparing beef and bison samples, injected SM muscle from bison had lower cooking losses than that from beef, whereas control samples from these two species did not differ in their cooking yields. Beef SM muscle was more tender than bison SM muscle; however, moisture enhancement was able to significantly reduce the shear force values of SM muscle roasts for both species (shear force values of 82N in control samples was reduced to 63N in injected ones). The cooking regimes, H45, H90 and UP, yielded products with significantly lower shear force values than that of the control. Based on the cooking yield and time involved, however, the H45 treat-ment performed the best. The results suggest that moisture enhancement of lesser value cuts of beef and bison SM

muscles followed by the appropriate cooking regime offers a new means of ensuring consistently tender products. Key Words: Marination, Cooking regime, Semimembrano-sus muscle EFFECTS OF MPSC RINSE AND CHILL TECHNOLOGY ON BEEF VISUAL CASE LIFE, PALATABILITY AND SHEAR FORCE AND LIVER PALATABILITY B. J. Reuter, D. T. Bartholomew, D. Timmerman e-mail: [email protected] Agricultural Utilization Research Institute The objective of this research was to evaluate effects of MPSC, Inc., Rinse and Chill technology (R&C) on visual case life, palatability and shear force of the longissimus muscle (LM) and triceps brachii (TB) as well as palatability on liver. Limousin steers (n = 40) were harvested in four groups at G&C Packing Company in Colorado Springs, CO. MPSC, Inc., Rinse and Chill technology was administered postexsanguination to 5 of 10 animals in each group. Liver samples were collected at harvest and packaged for later testing. At 48 h postmortem, carcasses were shipped to the BSI plant in Hartley, IA for breaking and the LM and TB were dissected from the left side of each carcass and vac-uum packaged. Shear force and visual case life were pre-formed on fresh samples on d9 and d9 through d21 post-mortem respectively. Muscle samples were frozen on d7 postmortem and cut into steaks for future evaluation. Tri-ceps brachii steaks from R&C carcasses had higher lean color case life panel scores (P 0.05) than control TB steaks from d0 through d8 and less discoloration (P 0.05) d2 through d6. Rinse and Chill TB steaks had a significantly lower percent of steaks deemed unacceptable on d5 and d6 with both R&C and control TB steaks less than 50 percent unacceptable between d7 and d8. Minolta a* values for R&C TB tended (P 0.1) to be higher d0 through d12 and b* values tended to be higher d0 through d5. Rinse and Chill LM steaks had higher lean scores (P 0.05) than control TB steaks from d0 through d6. Control LM steaks had less dis-coloration (P 0.05) d7 through d12. Control LM samples had a lower percent of steaks deemed unacceptable on d7 and d8 with R&C and control LM steaks reaching less than 50 percent unacceptable on d8 and d9 respectively. L* val-ues tended to be higher (P 0.1) for R&C LM steaks d0 through d9. Rinse and Chill TB steaks had higher (P = 0.06) sensory panel tenderness scores than control TB steaks. Shear force values for TB steaks were not significantly dif-ferent between R&C and control groups. Rinse and Chill LM steaks had lower (P = 0.04) shear force values than control LM steaks. Liver samples from R&C cattle had less flavor intensity (P = 0.03) and liver flavor (P = 0.02) than control liver samples. The results of this research support previous work done on Rinse and Chill technology as well as intro-duce new information about the technology. Key Words: Beef, Rinse and Chill


COMPARING PORK FAT COLOR FROM BARLEY AND CORN FED PORK USING IMAGE ANALYSIS T. P. Ringkob e-mail: [email protected] University of Nevada, Reno, NV The objective of this study was to compare pork fat color from a barley or corn diet with store-bought pork of un-known feeding regimes. A thin slice (~.5 cm) was cut from the 10-11 rib area of the pork loin. The slice was wrapped in film used for retail display and scanned on a HP 6350 flatbed scanner. Twenty-four pork loin chops were pur-chased at 3 local supermarkets. Small (1x2 cm) samples of subcutaneous fat were cut and placed on a tray over-wrapped with retail display film and scanned. The uncom-pressed tif files were imported into the IPLab image analysis program. The Japanese pork fat models were used as benchmarks. It was found that the yellow split of the CMY format produced linear results with a decent range. The image values for the yellow split of Japanese fat block mod-els were as follows: white fat block no. 1 # 66.5; no. 2 # 75.8; no. 3 # 86.7 and the slightly yellow no.4 # 96.0. The barley fed pork produced extra white fat (yellow split value of 54.9) which was even whiter than the Japanese no. 1 fat block model (66.5). The barley fed pork was much whiter (P<.05) than the corn fed pork which had a yellow split value of 90.6. The corn fed pork produced pork fat at the midpoint of the Japanese fat model no. 3. The yellow split value for the corn diet was not different (P<.05) from the store-bought pork (yellow split value of 91.6). Less than half of the corn fed and the store-bought samples would qualify for the Japanese export market (no. 1 and 2). However, 100% of the barley fed pork would qualify for the Japanese export market. Key Words: Pork fat color, Barley, Image analysis

1st Place, M.S. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods TENDERIZATION EFFECTS OF ELECTRICALLY PRODUCED HYDRODYNAMIC SHOCK WAVES ON TOP ROUND AND STRIP LOIN MUSCLES OF BEEF J.V.V. Sagili, J.R. Claus e-mail: [email protected] Department of Animal Sciences, University of Wisconsin-Madison Four experiments were conducted to evaluate the effective-ness of electrically generated Hydrodynamic Shockwaves (HSW) using a TenderClass™ System (TCS) to tenderize USDA Select beef top round (TR) and strip loin (SL) mus-cles. Experiment 1 was conducted on TR (n=20) to evaluate the uniformity in tenderization by HSW across the TCS processing tunnel (Hydrodyne Inc.). Experiment 2 deter-mined tenderization effects of HSW within SL (n=10) from the rib end through the sirloin end after removing a control steak from each end. Experiment 3 investigated whether the HSW treatment eliminates the need to age fresh and en-hanced SL (n=20). The HSW treated fresh (T) strip loins were compared to 2 reference controls (C1- not aged, C2-aged 14 d). The HSW treated and enhanced SL (not aged, TE) were compared to enhanced and aged controls (CE). The SL were injected (8% injection) with a solution contain-ing 0.25% NaCl and 0.4% sodium tripolyphosphate. In Ex-periment 4, SL (n=9) were used to compare blade tenderiza-tion (BT) with HSW tenderization. Tenderness was meas-ured by Warner-Bratzler shear force (WBSF) testing on the steaks cooked to 71C. Results from Experiment 1 indicated tenderness improvement (P<0.05) of 17 to 19% (WBSF re-duction) throughout the processing tunnel. Experiment 2 showed reduced (P<0.05) WBSF by 16.3% (C=3.79, T=3.17 kg) for rib end and 32.3% (C=4.46, T=3.02 kg) for sirloin end of SL. Experiment 3 indicated HSW treatment elimi-nated the need to age as C2 and T (3.09 and 3.16 kg, re-spectively) were equally effective in improving the tender-ness (P<0.05) compared to C1 (3.57 kg). Enhanced steaks were more tender than non-enhanced. Aged and enhanced controls were more tender than non-aged, enhanced HSW steaks (CE=1.62, TE=2.40 kg). In experiment 4, BT and HSW treatments equally reduced WBSF (P<0.05) compared to controls (C=4.53, T=3.38, BT=3.52 kg). Hydrodynamic shockwave processing of TR and SL muscles of beef pro-duced consistent tenderization in all the experiments. HSW treatment minimized the tenderness variation with reduced shear values within a muscle. In addition, the HSW treat-ment has the potential to eliminate the need for aging and could replace the existing blade tenderization process to tenderize meats. Key Words: Beef, Tenderization, Electrically generated shock waves


QUALITY ATTRIBUTES OF ENHANCED CASE-READY PORK LOIN CHOPS 1G. A. Searls, 1R. J. Maddock, 1D. M. Wulf, 2C. P. Allison, 2M. E. Doumit, 3T. W. Hothaus, 3R. C. Johnson e-mail: [email protected] 1South Dakota State University, 2Michigan State University, 3Farmland Foods This experiment evaluated quality attributes of case ready pork loin chops from three loin locations. Forty-five pigs representing two genetic lines and two sex classes (barrows and gilts) were randomly assigned to either a control diet (D1) or a diet containing 4.5g Paylean/day for two weeks prior to slaughter (D2). Boneless loins were obtained, pumped to a target of 112% of green weight and stored for one week. Three chops (C1, C2 and C3, 2.5 cm thick) rep-resenting the midpoint of each third of the loin (cranial, middle and caudal, respectively) were taken from each loin. Each chop was evaluated for quality characteristics (Day 6). Chops were retail packaged, placed in a modified atmos-phere master-pack, boxed and stored 12 d. On Day 18 postmortem, the master-packs were opened, the retail packages were placed in a simulated retail display setting and evaluated for quality characteristics. Chops were dis-played for 24 h and quality characteristics were re-assessed (Day 19). Warner-Bratzler Shear (WBS) force was deter-mined for each chop. Data was analyzed as a 2 x 2 x 2 x 3 factorial with main effects of finishing diet, genotype, sex and loin location and their two-way interactions. Loin pump and drip loss percentages were not affected (P >0.05) by any interactions or main effects. On Day 6, visual color did not differ among main effects, but L* and a* were af-fected by loin location with C3 being darker (P <0.05) than C1 and C2. Moreover, firmness differed by loin location with C3 being firmer (P <0.05) than C1 and C2. In addition, marbling differed by sex class with chops from gilts having lower marbling scores (P <0.05). On Day 18, color, firm-ness and marbling were affected (P <0.05) by genotype, with chops from genetic line 1 having higher L* values, lower firmness scores, and more visual marbling. In addi-tion, gilt chops had higher L* values (P <0.05) and lower (P <0.05) visual marbling scores. Similar to Day 6, firmness on Day 18 was affected by loin location with C3 being firmer (P <0.05) than C1 and C2. On Day 18, a finishing diet x genotype interaction was observed for marbling score where genetic line 1 pigs fed D2 had more marbling (P <0.05) than all other finishing diet x genotype combina-tions. Day 19 evaluations were similar to Day 6 with re-gards to firmness. On Day 19, pigs fed finishing diet D2 displayed more (P <0.05) marbling. Day 19 color scores (a* and b*) were affected by sex and loin location with gilt chops possessing lower a* and b* values (P <0.05) and C3 chops displaying higher a* and b* values (P <0.05) than C1 and C2. Additionally, WBS force evaluations were affected (P <0.05) by genotype, sex and loin location with chops from genetic line 1 being more tender, barrows being more tender, and C1 being more tender than C2 and C3, and C2 more tender than C3. In conclusion, quality attributes of

enhanced case-ready pork loin chops were significantly affected by production practices and location of chops within the loin. Key Words: Pork, Enhanced, Case-ready CONSUMER SENSORY ACCEPTANCE AND VALUE OF DOMESTIC GRAIN-FED, CANADIAN GRAIN-FED, AND AUSTRALIAN GRASS-FED BEEF STEAKS 1B. M. Sitz, 1C.R. Calkins, 1D. M. Feuz, 2W. J. Umberger, 1K. M. Eskidge e-mail: [email protected] 1University of Nebraska-Lincoln, Lincoln, NE, 2Colorado State University, Fort Collins, CO To determine consumer acceptance and value of beef from various countries, twenty-four taste panels of consumers (n = 273) were conducted in Denver and Chicago. Two pairs of steaks were evaluated for flavor, juiciness, tenderness, and overall acceptability on eight-point hedonic scales. One pair consisted of Australian grass-fed strip steak and domestic grain-fed strip steak. The other pair included Ca-nadian and domestic grain-fed strip steaks. The pairs were matched to similar Warner-Bratzler shear values and mar-bling scores to reduce variation caused by tenderness and juiciness between the steaks. Panelists were paid fifty dol-lars for participation in the taste panel. A n th price auction, a variation of the Vickery auction, used silent, sealed bids to determine the value the panelists placed on the samples. Steaks (0.45 kg) from the same strip loin sampled in the taste panel were auctioned. The panelists who won auc-tions paid for the steaks from their participation money. Consumers placed significantly higher (P <.0001) scores for flavor, juiciness, tenderness, and overall acceptability for domestic samples than Australian samples. A significantly higher (P <.0001) value was also placed on the domestic samples than the Australian samples. Domestic samples averaged 3.68 dollars/0.45 kg, while consumers placed an average value of 2.48 dollars/0.45 kg on Australian sam-ples. Consumers rated Canadian samples numerically lower for juiciness (P = .09) and lower (P <.005) for flavor, ten-derness, and overall acceptability than domestic samples. The willingness to pay for domestic samples was signifi-cantly higher for domestic samples (P <.01) versus Cana-dian samples. Consumers were placed an average value of 3.95 dollars/0.45 kg for domestic samples and 3.57 dol-lars/0.45 kg for Canadian samples. However, niche markets may be developed for the consumers who preferred the Australian grass-fed and Canadian samples over the domes-tic grain-fed samples. Consumers who preferred Australian grass-fed samples over domestic grain-fed samples (19.0%) paid 1.38 dollars/0.45 kg more (P <.0001). Consumers who favored the Canadian samples over the domestic grain-fed samples (29.3%) paid 1.37 dollars/0.45 kg more (P <.0001) for the Canadian samples. A majority of United States con-sumers appear to be accustomed to the taste of grain-fed beef and prefer domestic samples to beef from Australia grass-fed and Canada. Key Words: Beef, Feeding regime, Palatability


2nd Place, M.S. Division Graduate Research Poster Competition

sponsored by Sara Lee Foods MECHANICAL PROBES USED ON UNCOOKED STRIP LOINS CAN PREDICT COOKED LONGISSIMUS BEEF TENDERNESS J. W. Stephens, J. A. Unruh, M. E. Dikeman, M. C. Hunt, T. E. Lawrence, T. M. Loughin e-mail: [email protected] Kansas State University, Manhattan, KS Strip loins (IMPS 180) were used to evaluate the use of me-chanical probes and instrumental color to predict trained sensory panel (TSP) tenderness. In a preliminary study, un-cooked longissimus muscle (n = 29) was evaluated at 2 d postmortem with five mechanical probes and a spectropho-tometer to predict 14 d trained sensory panel (TSP) tender-ness. The most successful probes were the sharp needle, sharp blade and plumb bob probes, which were correlated with TSP tenderness (r = -0.77, -0.52, and -0.53, respec-tively). Fifty-three strip loins were used to develop regres-sion equations to predict TSP tenderness from combinations of probe peak force, total energy or cross product (peak force x total energy) measurements and instrumental color values. The predicted values of equations were also used to classify the strips into tenderness groups, and this classifica-tion was compared to the actual TSP tenderness. The sharp needle probe combined with L* predicted 49% of the varia-tion in TSP tenderness. Of the 41 strip loins predicted to be tender (predicted tenderness >5.0), 35 (85.4%) were actu-ally tender (TSP tenderness >5.0), and 9 of the 12 (75%) strip loins predicted to be tough (predicted tenderness <5.0) were actually tough (TSP tenderness <5.0). The sharp blade probe and L* equation predicted 50% of the variation in TSP tenderness, and that equation was correct in its classifi-cation of 35 of 40 (87.5%) strip loins as tender and 10 of 13 (76.9%) as tough. The plumb bob probe combined with L* predicted 47% of the variation in TSP tenderness. Of the 45 strip loins this equation predicted to be tender, 36 (80%) were actually tender, and 6 of the 8 (75%) strip loins pre-dicted to be tough, were actually tough. An equation using WBSF predicted 58% of the variation in TSP tenderness. The WBSF equation predicted 38 strip loins to be tender and 32 (84.2%) were actually tender and predicted 15 strip loins to be tough and 9 (60%) were actually tough. The sharp needle, sharp blade, and plumb bob probe prediction equations were comparable to WBSF in classifying strip loins into tenderness groups determined by a trained sen-sory panel. Key Words: Beef, Tenderness, Measurement

EFFECTS OF FINISHING PIGS USING A DEEP-LITTER, GROUP HOUSING SYSTEM OR A CONVENTIONAL CONFINEMENT HOUSING SYSTEM ON PORK MUSCLE QUALITY 1K. K. Sweeter, 1D. M. Wulf, 2R. Morrison, 2L. J. Johnston, 1R. J. Maddock e-mail: [email protected] 1South Dakota State University, 2University of Minnesota Two hundred eighty pigs, which resulted from the mating of Duroc boars with white maternal sows, were finished in either a deep-litter, group housing system (n = 160) or a conventional confinement housing system (n = 120) to de-termine the effects of housing system on pork muscle qual-ity. For the deep-litter, group housing treatment, pigs were finished on straw bedding in a hoop barn with two pens (n = 80 pigs each) allowing 1.86 m 2 per pig. For the conven-tional confinement housing treatment, pigs were finished on concrete, slatted floors in eight pens (n = 15 pigs each) al-lowing 0.74 m 2 per pig. All pigs were assigned to housing treatments at 34 kg live wt and fed the same corn-soybean meal based diet, with no supplemental fat, until a target market weight of 114 ±5 kg was reached. The pigs were transported approximately 400 km to a commercial slaugh-ter facility where they were harvested. Forty vacuum pack-aged, boneless pork loins, from a single harvest group (n = 20 per treatment), were retrieved from the commercial facil-ity for further analysis. At 7 d after the loins were packaged, purge loss, glucose in the purge, visual color scores, Mi-nolta L* values and visual marbling scores were evaluated for each loin. In addition, glycolytic potential, 48 h drip loss, cook loss and Warner-Bratzler shear force values were determined for each loin. Loins from the conventional con-finement housing treatment had higher NPPC marbling scores (2.88 vs. 2.34), less purge loss (1.51% vs. 2.27%), less drip loss (1.25% vs. 1.98%) and had lower shear force values (3.09 kg vs. 3.50 kg) than loins from the deep-litter, group-housing treatment (P <0.05). Color, pH, glucose in the purge, and glycolytic potential did not differ between housing treatments (P >0.05). Overall, pigs finished in a conventional confinement housing system had loins with higher muscle quality than pigs finished in a deep-litter, group housing system. Key Words: Pork, Housing, Muscle Quality


AGING AND ENHANCEMENT EFFECTS ON SENSORY CHARACTERISTICS OF BEEF STRIP STEAKS S. Wicklund, F.K. McKeith, M.S. Brewer e-mail: [email protected] University of Illinois, Urbana-Champaign, IL The Longissimus was removed 24 h postmortem from 20 paired beef sides to assess the effects of enhancement and aging time on quality attributes of beef strip steaks. Sides were pumped to 108% of original weight to contain .4% sodium phosphate, .4% salt, and added water for compari-son with unpumped samples. Ten paired sides were then cut into four sections and aged 7, 14, 21, and 28 days. The remaining ten paired sides were cut into 2 sections, aged 7, 14, 21, and 28 days. Following aging, two steaks were re-moved and the remainder of the section was for comparison with unpumped samples. The steaks (2.5 cm thick) were grilled to an internal temperature of 70 ºC and evaluated by an 8 member trained sensory panel. Sensory characteristics evaluated included tenderness, juiciness, saltiness, and me-tallic off-flavor intensity. A 2(pump level) x 4(aging time) factorial design was used for statistical analyses. There was an interaction (p<0.05) between pump level and aging pe-riod for tenderness when the samples were enhanced prior to aging. There was a trend for tenderness, juiciness, and saltiness to be enhanced by pumping while metallic off-flavor was inhibited for samples enhanced prior to aging. This trend was also seen in samples that were aged prior to enhancement with the exception that there was no signifi-cant difference in metallic off-flavor. Tenderness and juici-ness were significantly affected by aging time in samples that were enhanced prior to aging. The samples aged 28 d were more tender, while no significant difference between aging 7, 14, and 21 d was found. The samples aged 7 d were juicier, but no significant difference was seen between 14, 21, and 28 d. There was a significant difference be-tween the samples enhanced prior to aging and those en-hanced after aging. The samples were more tender and juic-ier in the samples enhanced prior to aging than in samples enhanced after aging. There was an interaction (p<0.05) between pump level, aging period, and time of enhance-ment for tenderness, saltiness, and juiciness. Results of this study show that pumping beef loins prior to aging allows for decreased aging periods while increasing appealing charac-teristics (tenderness and juiciness) and inhibiting unappeal-ing characteristics (metallic off-flavor). Key Words: Beef, Sensory, Aging THE EFFECT OF USDA QUALITY GRADE, DEEP MARINATION, AND DEGREE-OF-DONENESS ON PALATABILITY OF GAS-GRILLED BEEF STEAKS FROM SEVEN DIFFERENT MUSCLES B. A. Streff, D. M. Wulf, R. J. Maddock e-mail: [email protected] South Dakota State University

The objective of this study was to determine the effects of USDA quality grade, deep marination, and degree-of-doneness on palatability of gas-grilled beef steaks from seven different muscles. A 7 X 3 X 2 factorial design was used involving seven muscles: gluteus medius (GM), infrap-inatus (IF), longissimus (LD), psoas major (PM), rectus femo-ris (RF), serratus ventralis (SV), and triceps brachii (TB); three classes: top choice (TCH), USDA select (SEL), and deep-marinated USDA Select (DMS); and two degrees-of-doneness: 63ºC and 79ºC. The experiment was replicated ten times for taste panel evaluation and 14 times for shear force assessment. Certified Angus Beef™ (used for TCH) and USDA Select subprimals were purchased commercially, aged 14 d from box date at 3ºC, and then frozen. One-half of the USDA Select subprimals were pumped 1 d prior to freezing to 108% of green weight with a brine consisting of 91.9% water, 5.0% salt, and 3.1% sodium tripolyphosphate for the DMS class. Steaks (2.5-cm-thick) were cut from fro-zen subprimals and randomly assigned to degree-of-doneness level and shear force or taste panel. Steaks were thawed 24 h at 3ºC, seasoned with salt and black pepper, and grilled on popular consumer-model liquid-propane grills. Steaks cooked to 63ºC had lower shear force, were more tender and juicy, and had more intense beef flavor than steaks cooked to 79ºC (P<0.05). Top choice steaks had lower shear force, were more tender and juicy, and had more intense beef flavor than SEL steaks (P<0.05). Deep-marinated USDA Select steaks had lower shear force, were more tender and juicy, and had more intense beef flavor than SEL steaks (P<0.05). Deep-marinated USDA Select steaks were more tender and had more intense beef flavor than TCH steaks (P<0.05). The interaction of degree-of-doneness and class was significant only for shear force, and indicated that both marbling and deep marination had greater effects on shear force when steaks were cooked to 79ºC versus 63ºC. Muscles differed more in tenderness rat-ings than in juiciness or flavor intensity ratings and ranked from most tender to least tender as follows: PM >IF >LD and RF >SV, TB, and GM (P<0.05). Of the seven muscles, the IF had the most and the LD had the least total off-flavors (P<0.05). Psoas major and IF steaks had the highest and second highest incidence of livery off-flavors, respectively. The interaction of muscle and degree-of-doneness was sig-nificant for all palatability traits; palatability of SV steaks was only slightly affected by degree-of-doneness, whereas palatability of GM and LD steaks was much lower at 79ºC versus 63ºC. The interaction of muscle and class was sig-nificant for shear force and panel tenderness; higher mar-bling (TCH versus SEL) resulted in more tender IF, LD, SV, and TB steaks (P<0.05), but had no effect on tenderness of GM, PM, and RF steaks (P>0.05). While deep marination improved tenderness in most of the muscles tested, the greatest improvement was observed in LD and TB steaks (P<0.05). In conclusion, DMS steaks had palatability attrib-utes equal to or greater than TCH steaks, but the effects of deep marination and marbling were greater at higher de-grees-of-doneness and varied by muscle. Key Word: Enhancement, Meat cooking, Palatability


Processed Meats & Ingredient Technology

THE EVALUATION AND COMPOSITION OF BEEF SEMITENDINOSUS UTILIZING A COOK-OUT PURGE COLLECTION SYSTEM B.L. Booren, J.L. Baumert, R.W. Mandigo e-mail: [email protected] University of Nebraska-Lincoln Cook-out purge, commonly an under-utilized product, is typically discarded by meat processors. The utilization of cook-out purge by a meat processor would increase the value of the meat item. The effect of cooking dwell time on the chemical and physical properties of cooked meat and cook-out purge utilizing a cook-out purge collection system was examined. Beef semitendinosus (n=48) muscles were randomly assigned a cooking dwell time of 0, 60, 90, or 120 min within a treatment combination of added level of a 3% salt and 0.3% sodium phosphate enhancement solution (0% or 12%) and internal endpoint temperature (60ºC or 65ºC). The cooked meat and cook-out purge yields were not affected (P>0.05) among cooking dwell times for sam-ples with 12% added enhancement solution. Warner-Bratzler Shear and Lee-Kramer Shear values for cooked meat tenderness resulted in differences (P<0.05) among cooking dwell times, as did moisture, ash, fat and protein levels of cooked meat. Cook-out purge samples had no dif-ferences (P>0.05) among cooking dwell times for moisture, ash, fat, and total collagen levels. Protein levels for cook-out purge resulted in a difference (P<0.05) among cooking dwell times. The addition of a 12% enhancement solution may decrease the variation cooking dwell time has on the chemical and physical properties of cooked meat and cook-out purge. This may be beneficial to meat processors in creating a meat product that utilizes cook-out purge as the only component affected by cooking dwell time is the level of protein. The amount of protein found in cook-out purge may be affected by altering the components and levels within the enhancement solution, which could be used for other functions within a food product like sauces and gra-vies. Key Words: Cooked beef composition, Cook-out purge composition, Cooking dwell time

EFFECTS OF THE ADDITION OF VARIOUS BINDERS ON QUALITY CHARACTERISTICS OF SAUSAGE PREPARED IN A MODEL SYSTEM R.L. Husak, D.R. Doerscher, G. Prabhu e-mail: [email protected] Proliant Inc., Ames, Iowa, USA Researchers have frequently used meat model systems, such as sausage type emulsions prepared under laboratory conditions, to study the effects of various binders on the functionality of meat batters. Model systems allow for more precise control of external processing parameters. Binders such as starches and soy proteins are commonly added to meat products to improve water retention, consistency, texture, and sliceability. Other binders such as collagen proteins, plasma proteins, and whey proteins can also provide functionality in processed meat sys-tems. The objective of this study was to compare the water binding and texture modifying performance of several different binders using a sausage model system. The model system was formulated with a master blend consisting of beef (80% lean) and pork (80% and 50% lean). The meat was first ground through a 1/8" plate. The lean meat was mixed with half of the water, salt, phosphate, sodium erythorbate, and sodium nitrite for 3 min. Then the fat meat was added and mixed for an addi-tional 2 min. The binders used in this study were 1.0% soy protein concentrate (SPC), 1.0% modified corn starch (MCS), 1.0% beef plasma (BP), 1.0% pork collagen (PC), and 1.0% whey protein concentrate (WPC). The master blend was di-vided into 250g batches and the binders were mixed into each batch at the above mentioned usage levels, recommended by the manufacturer. The mixture was then stuffed into plastic test tubes and cooked in a water bath at 72ºC for 30 min. The samples were then held overnight at 8ºC. Triplicate measure-ments of processing yield, texture, proximate analysis, and color were measured for all treatments. Data indicated that there was a significant increase (P<0.05) in processing yield for the MCS treatment when compared to treatments containing SPC, BP, and WPC. However, the texture of the MCS treatment decreased significantly (P<0.05) compared to the SPC, BP, PC, and WPC treatments. In addition, proximate analysis provided differences between treatments, but data did not support prac-tical trends across treatments. The color observations of L*, a*, and b* expressed no significant difference (P>0.05) across all treatments. As the data indicated, each binder achieved differ-ences in processing yield, texture, and proximate analysis ena-bling processors to use this data to choose desirable final prod-uct attributes. Key Words: Sausage, binders, model system




APPLICATION OF ACID SOLUBILIZATION ISOELECTRIC PRECIPITATION TO PORK PRODUCTS J.M. James, C.A. Mireles Dewitt e-mail: [email protected] Oklahoma State University, Stillwater, OK An evaluation of an alternative process has been investi-gated for its potential to improve low valued red meat products. The acid solubilization isoelectric precipitation (SIP) method is used to obtain a more functional and stable protein concentrate from low valued meat products. This process takes advantage of differences in protein solubility to separate myofibrillar proteins from collagen, fat, and bone. Our previous research has established the applicabil-ity of using beef heart to extract proteins that have accept-able nutritional, compositional, and binding properties, but more work was needed to determine if the process could be used with red meat from different species and on products that contained higher levels of fat and bone. The objective was to determine the composition and characteristics of pork heart (PH) and pork meat and bone meal (PMB) when utilizing Acid-SIP. Protein obtained from PH Acid-SIP and PMB Acid-SIP derived from the picnic shoulder were ad-justed to 78% moisture and treated with or without 2% NaCl. Proximate analysis, color, and cholesterol were evaluated for each raw treatment. The remaining protein from each treatment was stuffed into 21 mm cellulose cas-ing and cooked in a 90ºC water bath for 30 min. Proximate analysis, color, water holding ability (WHA), cook yield, and textural properties were determined for each cooked treatment. The PMB Acid-SIP extracted proteins had signifi-cantly less fat, cholesterol, and ash than the original meat and bone meal. Both Acid-SIP proteins from PH and PMB showed good WHA (2.23±0.53 g water/g protein and 2.25±0.37 g water/g protein, respectively) and cook yield (99.79±2.85% and 92.94±3.20%). Texture Profile Analysis (TPA) of the cooked links further demonstrated the gelling ability of the proteins. Based on results, utilizing Acid-SIP on PH and PMB improves nutritional composition and tex-tural properties. Further work needs to be done to see if this method would have an economic value for applying the process to mechanically separated meat and other byprod-ucts. Key Words: protein solubilization, gel functionality, by-products EFFECT OF ANTIOXIDANTS ON STABILIZATION OF MEAT PRODUCTS WITH n-3 FATTY ACIDS 1S Lee, 2D Djordjevic, 2Y Park, 1C Faustman, 2E Decker e-mail: [email protected] 1University of Connecticut, Storrs, CT, 2University of Massa-chusettes, Amherst, MA Muscle food products from terrestrial livestock have the potential to be fortified with long chain n-3 polyunsaturated fatty acids (PUFAs) and thus serve as a source of this impor-tant nutrient class. However, n-3 PUFA fortification may

enhance the susceptibility of muscle food products to lipid oxidation. The objective of the present study was to deter-mine an optimal combination of antioxidants to minimize lipid oxidation in n-3 PUFA - fortified meat products. An emulsion of n-3 PUFAs was prepared (25% algal oil, 2.5% whey protein isolates, 10 mM sodium citrate, 0.2% potas-sium sorbate, 500 ppm of 70% Mixed tocopherols, 100 mM EDTA, pH 3, pasteurized at 75ºC for 30 min) and incorpo-rated into fresh ground turkey, and fresh ground pork sau-sage (20% fat) to achieve a concentration of 500 mg n-3 PUFA/110 g meat. An ´antioxidant cocktail´ containing rosemary (0.2% w/w; radical quencher), citrate (0.5% w/w; sequestrant) and erythorbate (1g/kg product; reductant) was prepared and incorporated into ground turkey patties (5 cm dia, 1.5 cm thick) or pork breakfast sausages (7.5 cm dia. � 25 cm length). These were stored at 4ºC or -18ºC and ana-lyzed for color (L*, a*, b* value), lipid oxidation (TBARS and peroxide value) and n-3 PUFA profile. a* Values of refrigerated ground turkey patties decreased with storage , but no antioxidant cocktail effect was observed until 4 days (p>0.05). For refrigerated breakfast sausages, con-trol+antioxidant (CON+ANTI) and n-3+antioxidant (n-3+ANTI) groups showed higher a* values than controls (CON) indicating that the antioxidant cocktail played a sta-bilizing role toward meat color. TBARS and peroxide values of both n-3 PUFA enhanced meat products increased mark-edly with storage time (p<0.05) compared to other treat-ment groups, and there were no significant changes in TBARS values or peroxide values over time for treatments containing the antioxidant cocktail (p<0.05). The recovery of n-3 PUFA in both meat products was greater than 90 %; there was no difference in n-3 PUFA concentration within any treatment during storage (p<0.05). These results provide support for including antioxidant protection in n-3 PUFA fortified meat products for the purpose of minimizing lipid oxidation. Key Words: n-3 PUFAs, fortification, meat color, antioxi-dant, lipid oxidation REDUCING LIPID OXIDATION IN IRRADIATED GROUND BEEF PATTIES BY NATURAL ANTIOXIDANTS I. Movileanu, J.T. Keeton e-mail: [email protected] Texas A&M University Meat irradiation is a proven bactericidal process that en-ables "pasteurization" of raw meat while reducing the risk of Escherichia coli O 157:H7 contamination and retarding the germination of Clostridium botulinum spores through com-petitive inhibition by surviving spoilage bacteria. The free radicals and hydroperoxides generated by irradiation can increase lipid oxidation, produce off-flavor compounds re-duce organoleptic properties, and destroy endogenous anti-oxidants. Therefore, this study was performed to compare the antioxidant properties of dried plum puree, butylated hydroxyanixole/butylated hydroxy toluene (BHA/BHT), and


rosemary extract in irradiated (0,1.5, or 2.0 kGy) ground beef patties. Fresh ground beef patties containing 20% fat with (1) no antioxidant, (2) 0.02% BHA/BHT,(3) 3% dried plum puree, or (4) 0.25% rosemary extract were packaged under partially aerobic conditions, irradiated at 0, 1.5, or 2.0 kGy (actual levels were 1.7 or 2.3 kGy), and stored at 4°C. The samples were evaluated for thiobarbituric acid (TBARS) values, sensory descriptive attributes, subjective color, and color space values after 0, 3, 7, 14, 21, and 28 days. For statistical validity, three batches of the experiment were conducted. Statistical analyses of the date were per-formed using the General Linear Model of the SAS system. Least square means of the main effects and interactions were analyzed for significance at P<0.05. All antioxidants were effective for retarding oxidative rancidity, as deter-mined by TBARS values, in irradiated (1.5, 2.0 kGy targets; actual average levels 1.7, 2.3 kGy) ground beef patties stored at 4oC for 28 days. Rosemary (0.25%) and BHA/BHT (0.02%) were the most effective antioxidants. Dried plum puree (3%) also decreased lipid oxidation during storage, but was not as effective as the other antioxidants. The L* and b* color space values were not affected by irradiation dose, but 2.0 kGy irradiation caused redness (a*) values to decrease on day 0 and day 28. No differences in redness were noted among treatments over the remaining storage period. Subjective ground beef color (GBC) did not differ from the control during the storage period, but the percent surface discoloration after day 0 increased from 1-19% to 20-39% and then remained unchanged. Dried plum puree slightly increased the amount of surface discoloration (AMDSC), possibly due to the color of the puree. Irradiation dose at 1.5 and 2.0 kGy lightened GBC (surface meat color) at day 0 resulting in a moderate cherry red and very light cherry red appearance, respectively but remained un-changed over the storage period. Descriptive sensory analy-sis showed only very small changes in sensory attributes over the storage period. Sensory differences of all treat-ments, when significant, were only marginally different, usually less than 1 unit difference on a 16 point scale. rra-diation dose changes were only marginally detectable for sensory attributes Key Words: Lipid oxidation, Meat irradiation, Antioxidants THERMAL DENATURATION OF MYOSIN IN CHICKEN MYOFIBRILS SUBJECTED TO OXIDATION BY HYDROXYL RADICAL-GENERATION SYSTEMS T. Ooizumi, Y.L. Xiong e-mail: [email protected] Department of Animal Sciences, University of Kentucky Oxidation of myofibrillar proteins is believed to be involved in quality changes of fresh and processed muscle foods dur-ing storage. Recent studies have suggested that these quality changes, especially decreases in gel-forming ability, are related to destabilization of myosin caused by oxidation. However, little information is available regarding the dena-turation process of oxidized myosin. The objective of the

study was to elucidate which portion of myosin was desta-bilized, i.e. subfragment-1(S-1), rod, or both by means of thermal analysis of oxidatively stressed myosin. Myofibrils prepared from commercial postrigor chicken breast muscle were treated with non-enzymatic, hydroxyl radical-generation systems (HRGS) consisting of 0.1 mM ascorbic acid, 0.01 mM ferric chloride, and 0.1-5 mM of hydrogen peroxide at 0ºC for 18 h. Oxidized myofibrils were washed with a 0.1 M potassium chloride, 20 mM Tris-HCl (pH 7.5) buffer to remove HRGS, and subsequently subjected to heat treatment at 45-49ºC for up to 24 h. Changes in myosin Ca-ATPase activity and salt solubility as well as chymotryptic production of S-1 and rod from myosin were monitored as indices of the thermal denaturation process of myosin. Ca-ATPase (0.2 mg/ml myofibrillar protein) was assayed in the medium of 0.5 M potassium chloride, 5 mM calcium chlo-ride, 25 mM Tris-maleate (pH 7.0), and 1 mM ATP at 25ºC. Salt solubility of myosin was densitometrically determined from SDS-PAGE of salt soluble fraction of the oxidized myo-fibrils in 0.5 M potassium chloride with 1 mM ATP-Mg. Chymotryptic digestion of myofibrils was carried out in the medium of 0.1 M potassium chloride with 1 mM EDTA, and the production of S-1 as well as rod was determined by densitometry of SDS-PAGE. HRGS treatment of myofibrils caused cross-linking of myosin heavy chains via disufide bonding and an increase in Ca-ATPase activity, suggesting that thiol groups of myosin including those at the active site were modified. On the other hand, salt solubility and chy-motryptic digestibility of myosin was not affected by HRGS treatment. HRGS treatment promoted thermal inactivation and insolubilization of myosin, confirming that oxidation of myofibrils decreased thermal stability of myosin. Further-more, a decrease in chymotryptic production of S-1 and rod from myosin by heat treatment of myofibrils was ob-served.The S-1 production from myosin in the oxidized myofibrils decreased more rapidly than that in unoxidized myofibrils. The decrease in S-1 production by heat treat-ment was in accordance with the Ca-ATPase decay. How-ever, the HRGS treatment did not affect chymotryptic pro-duction of rod from myosin by heat treatment. The results strongly suggested that destabilization of myosin due to oxidation occurred in the S-1 portion rather than the rod portion. The altered myosin denaturation pattern as induced by oxidation may explain functionality changes in oxida-tively stressed myofibrillar proteins including gelation. Key Words: Myosin, Oxidation, Denaturation


PARTICLE SIZE AND NON-MEAT ADJUNCT EFFECTS ON THE PROTIN FUNCTIONALITY OF BONELESS CURED PORK FORMULATED WITH PSE AND RFN RAW MATERIAL 1M.W. Schilling, 2C.Z. Alvarado, 1N.G. Marriott e-mail: [email protected] 1Virginia Polytechnic Institute & State University, 2Texas Tech University Utilization of pale, soft, and exudative (PSE) pork in the formulation of processed meat products leads to decreased water holding capacity, pale cooked color, and insufficient protein-protein binding. Incorporation of either 25 or 50 % PSE raw material combined with soy protein, starch, milk protein, and/or carrageenan in the formulation of boneless cured pork is an effective outlet for this low value raw mate-rial. In this experiment, boneless cured pork was produced from a combination of 25 % PSE and 75 % red, firm, and non-exudative (RFN) semimembranosus muscle. A random-ized complete block design with six replications was util-ized to test the treatment effects of adjuncts (no adjuncts, 2 % soy protein concentrate (SPC), and 2 % SPC +1.5 % modified food starch (MFS)) and raw material size (2.54 cm*2.54 cm and 10.16* 5.08 cm) on protein functionality in a 3*2 factorial design. CIE L *, CIE a *, CIE b *, cooking loss, expressible moisture, and protein-protein bind were measured for all treatments. Utilization of the smaller raw material size decreased (p<0.05) expressible moisture, CIE L*, and CIE b*, providing increased functionality through increasing water holding capacity and improving color. Utilization of the smaller raw material size also decreased (p<0.001) protein-protein bind. This result is not crucial since all treatments exhibit excellent bind (>2.3 kg peak force). SPC increased (p<0.05) lightness and yellowness, but no adjuncts affected any other protein functionality meas-urement. Under these experimental conditions, SPC and MFS had minimal effects on protein functionality. Product formulations utilizing smaller particle size in a chunked and formed product demonstrate the potential to improve the water holding capacity and cooked color in deli ham rolls formulated from a combination of 25 % PSE and 75 % RFN pork. Key Words: PSE, Water holding capacity, Cooked color THE EFFECTS OF REDUCING AGENTS ON PREMATURE BROWNING IN GROUND BEEF H. A. Sepe, C. Faustman, S. Lee, J. Tang, S. Suman e-mail: [email protected] University of Connecticut, Storrs, CT Research has shown that ground beef patties will appear brown (i.e. done) before they have reached the USDA rec-ommended internal temperature of 71 ºC. This may lead to consumption of ground beef that has not been properly heat-treated to kill significant food-borne pathogens. The objective of this study was to investigate the effects of food-grade reducing agents on counteracting premature brown-

ing. Sodium erythorbate (SE), erythorbic acid (EA), sodium ascorbate (SA), ascorbic acid (AA), and ascorbyl palmitate (AP) were added to ground beef (15% fat) at a concentration of 2.3 mM. Beef was made into patties, wrapped and stored at 4 ºC for 48 hrs or frozen at -18 ºC for 14 days. Color (L*, a*, b*) was measured before and after cooking to internal temperatures of 65 ºC, 71 ºC, and 77 ºC. Lipid oxidation (TBARS; thiobarbituric acid reactive substances) and reduc-ing activity were measured for raw patties. All reducing agents decreased lipid oxidation and increased the reducing activity of raw patties when compared to controls (p <0.05). Measured a* values (redness) of raw patties containing SE, EA, SA, and AA were higher than those of controls after refrigerated storage, but lower than those of controls after frozen storage (p <0.05). For refrigerated samples, addition of SE, EA, SA, and AA resulted in higher internal a* values compared to controls when cooked to 65 ºC (p <0.05). Only patties containing SE and SA had higher internal a* values when cooked to 71ºC (p <0.05). There was no differ-ence for a* values between treatment and control patties when they were cooked to 77 ºC (p >0.05). Frozen patties containing SE, EA, and SA had higher internal a* values compared to controls when cooked to 65 ºC or 71 ºC (p <0.05). When frozen patties were cooked to 77ºC, addition of SE and SA resulted in higher internal a* values compared to controls (p <0.05). In general, SE and SA were more ef-fective at maintaining red color and preventing premature browning in ground beef. Key Words: Premature browning, a* values, reducing activ-ity PREDICTION OF INTER-MUSCULAR FAT IN THE FRESH PORK LEG 1A. J. Stetzer, 2R. E. Klont, 2A. A. Sosnicki, 1F. K. McKeith e-mail: [email protected] 1University of Illinois at Urbana-Champaign, Urbana IL, 2PIC USA, Franklin, KY This experiment was carried out to quantify the relationship of linear carcass measurements to star fat in hams and to predict the amount of star fat in hams. A total of 90 car-casses (45 gilts and 45 barrows) of the same genetic back-ground were selected based on hot carcass weight at ranges of 70.8 to 83.6 kg, 84.4 to 90.4 kg, and 90.9 to 98.9 kg (L, M and H groups, respectively). Paired fresh pork legs (n = 178) were utilized in which the left side was processed into hams for center cut slice area measurements and processing yields. Right side fresh pork legs were utilized for fresh ham composition and cutting yields. In addition, three subcuta-neous fat thicknes points (midpoint, ventral and dorsal) were measured on the right ham at the position where a center cut slice would be removed. Selection based on hot carcass weight resulted in a wide range of fat and lean measurements. Mean ham weights ranged from 8.09 to 12.07 kg, and last rib fat ranged from 0.76 to 3.05 cm. Ham weights also varied for the left side of 11.26, 10.64, and 9.82 kg and for the right side of 11.19, 10.53, and 9.66 kg


(H, M, and L, respectively). Also, last rib fat was different for barrows (2.49 cm) and for gilts (2.16 cm;P<0.05). Star fat weight increased with the weight groups (0.08, 0.10 and 0.11 kg, respectively for L, M and H;P<0.05). Linear fat measurements did not consistently predict star fat weight. Star fat area measurements had a correlation to seam fat weight (0.29). The three subcutaneous fat depth measure-ments taken at the midpoint, ventral and dorsal sites had moderate correlations of (0.17, 0.19 and 0.19, respectively) to star fat weight. However, these midpoint, ventral and dorsal fat depth measurements had higher correlations to seam fat (0.35, 0.29 and 0.28, respectively) and subcutane-ous fat (0.76, 0.72 and 0.71, respectively). Both, seam and subcutaneous fat can explain a portion of the variation in star fat weight using cubic (R 2 = 0.27) and linear regres-sions (R 2 = 0.30), respectively. In addition, hot carcass weight can explain a portion of the variation in star fat weight using cubic regression (R 2 = 0.27). By utilizing a few key variables, star fat weight could be minimized in ham production. Key Words: Pork, Composition, Ham EFFECT OF ERYTHORBATE, STORAGE AND PACKAGING ON PREMATURE BROWNING IN GROUND BEEF S.P. Suman, C Faustman, S Lee, J Tang,PVasudevan, T An-namalai, M Manojkumar,PMarek, K.S. Venkitanarayanan e-mail: [email protected] University of Connecticut, Storrs, CT The color of cooked ground beef is often used as an indica-tor of doneness. For safety reasons, it is recommended that the center of ground beef products be cooked to 71ºC. Pre-mature browning (PMB) is the condition in which beef may appear done before reaching 71ºC. Ground beef with added erythorbate at 0.04%(ERY), and without erythorbate (CON), was formed into patties. In Experiment 1, patties were stored at 4ºC for 48 hr (REF), or at -18ºC for 21 days (FROZ), or frozen at -18ºC for 21 days, thawed at 4ºC for 24 hr (F-T), and cooked. Bulk ground beef (0.5kg) was stored (BULK) at -18ºC for 24 days, thawed for 24 hr at 4ºC, and patties pre-pared and cooked immediately. In Experiment 2, patties were overwrapped with PVC film (WRAP) or packed in Modified Atmospheres (80% O2 and 20% N2), stored for 48 hr at 4ºC (MAP), or frozen for 21 days at -18ºC (MAPF) and cooked. Total reducing activity (TRA) of the meat was measured immediately prior to cooking. The patties were cooked to internal end point temperatures of 60º, 66º, 71º and 77ºC. External raw color and internal cooked color ( L*, a* and b* values) were measured. TRA was higher for ERY for all storage conditions; FROZ ERY patties had higher TRA than F-T ERY and REF ERY treatments ( P<0.05). After 48 hr MAP storage at 4ºC, TRA was lower for CON and ERY when compared to their aerobically packaged counterparts ( P<0.05). Beef with 0.04% erythorbate and cooked to in-ternal temperatures of 60º, 66º and 71ºC had higher a* val-ues than CON ( P<0.05). The a* values for cooked patties were higher for ERY than CON under all storage and pack-

aging conditions at 60º and 66ºC ( P<0.05). The presence of erythorbate in ground beef patties appeared to maintain red color at cooked internal temperatures of 60º and 66ºC and to prevent premature browning. MAP did not exert any ef-fect relative to conventional fresh meat wrap packaging for patties stored at 4ºC for 48 hr and cooked. Key Words: Premature Browning, Ground beef, Erythorbate THE EFFECT OF HAND TRIMMING, MECHANICAL PRESSING, AND STORAGE TIME ON CHEMICAL AND PHYSICAL PROPERTIES OF SOUS VIDE LAMB SHOULDER IN CURRY SAUCE P. Udomvarapant, E.A. Boyle, L.S. VanderWal, D.H. Kropf, C.L. Kastner, R.J. Danler, T.M. Loughin e-mail: [email protected] Kansas State University, Manhattan, KS Sheep meat is objectionable to some people due to its strong, unique odor and flavor as well as a waxy mouthfeel caused by fat. To encourage lamb meat acceptance in U.S. and utilization of low value portions of carcasses, a sous vide lamb shoulder product was prepared. The objective of this trial was to discover practical and least cost methods in terms of labor and time to remove fat, and to study the ef-fect of these fat removal methods and storage time on chemical and physical properties of lamb products. Bone-less lamb shoulders were trimmed by hand and then cut into 2.54cm 3 cubes -untrimmed, coarsely trimmed, and closely trimmed (22%, 14%, and 6% fat respectively). Half of untrimmed and coarsely trimmed cubes were precooked to 70-75ºC in hot water and pressed by modified Instron (490Kgf and 10 mm/min speed) to create pressed un-trimmed and pressed coarsely trimmed meat (25 and 14% fat respectively). For each treatment, samples of 227g of lamb cubes were mixed with the same amount of curry sauce (Creative Seasonings&Spices, Inc., Sturtevant, WI), and then anaerobically cooked in heat-resistant bags in smokehouse, holding meat at 90ºC for 2h. All products were chilled immediately by cool water following USDA regulation, and kept at 4ºC for examinations at 1, 30, 60, 90, 120, and 150 days. All 5 treatments were replicated 3 times, in a strip-split plot design. The data was analyzed by SAS. The proximate analysis of meat (raw material) was determined. Cooked lamb meat was evaluated for tender-ness (fork tenderness, initial tenderness, and fiber break-down), sheep meat aroma and taste, oxidative rancidity, and fat-mouth coating traits by 6-12 trained panelists on 6-point scale. Objective tenderness by Lee Kramer Shear, pH, TBARS, and color (CIE L*, a*, and b*) were examined. Hand trimming was effective in removing fat composition in meat cubes (p<0.05). The heating/pressing methods caused an increase of fat level in untrimmed category (p<0.05), but did not affect fat of coarsely trimmed lamb (p>0.05). They decreased subjective tenderness as well as L* and b* value, but increased TBARS. Pressed meat was evaluated between ''slightly tender and moderately tender'', but non-pressed items were ''moderately tender''. Objective tenderness


trend was similar to subjective tenderness. Panelists found ''no rancidity'' in all samples at d1, but gradually detected stronger rancidity when the products were kept longer. The meat at d120 was less acceptable and scored ''slight rancid-ity detection''. Sheep meat aroma, sheep meat taste, fat-mouth coating, and pH was not affected by fat trimming, pressing, nor storage time (p>0.05). Closely trimmed prod-uct was the most desirable, but time consuming with high labor cost for preparation. Coarsely trimmed meat was an accepatable raw material, whereas untrimmed lamb showed high variation in product qualities. None of fat re-moval methods by heating/pressing was successful. Key Words: sous vide , lamb meat , storage time DETERMINATION OF OPTIMUM USAGE LEVELS OF VARIOUS ANTIOXIDANTS IN COOKED GROUND MEAT Mihir Vasavada, D.P. Cornforth e-mail: [email protected] Utah State University, Logan UT / USA According to USDA regulations, butylated hydroxytoluene (BHT) may be added as an antioxidant in fresh pork sausage at 0.01% of fat content. However, our previous work showed that this level (0.01% of fat weight) was too low to inhibit rancidity after cooking. We similarly found that 0.2% rosemary oil (% of meat weight) was not inhibitory to lipid oxidation in cooked ground pork. Thus, the objective of this study was to determine the effective usage level for BHT and rosemary in cooked ground pork. We also evalu-ated cumin and coriander as antioxidants in cooked ground beef as measured by the thiobarbituric acid (TBA) value. After 15 days storage, cooked pork samples with 0 (control), 0.002, 0.01 and 0.02% BHT had mean TBA values of 5.0, 4.8, 2.0 and 1.8 respectively. Thus, a minimum of 0.01% BHT (% of meat weight) was needed to obtain antioxidant effects in cooked ground pork.Rosemary oil at 0.05-0.2% of raw meat weight was not effective for inhibition of lipid oxidation of cooked ground pork. Ground rosemary at 0.4-0.8% was very effective in maintaining TBA values at 1.0 or less after 15 days of storage at 2°C. 0.1% coriander inhib-ited oxidation in cooked ground beef as compared to con-trols, but 0.5% cumin was required for antioxidant activity. Key Words: antioxidant, rosemary, BHT THE EFFECTS OF NON-MEAT INGREDIENTS, BLADE TENDERIZATION AND VACUUM-TUMBLING ON HIGH CONNECTIVE TISSUE CUTS OF BEEF 1T.A. Williams, 1R.K. Miller, 1J.T. Keeton, 1L. Rooney e-mail: [email protected] 1Texas A&M University Use of non-meat ingredients to extend shelf-life, enhance flavor and color, and improve palatibility of beef steaks in high oxygen, modified atmosphere retail packaging has become a beef industry practice. However, beef muscles vary in physical and chemical characteristics due to their

function within the animal. Therefore, they vary in color, pH, drip loss and palatibility. The challenge is to develop a processing system for individual muscles that would maxi-mize color, package purge or drip loss, and palatibility in high oxygen, modified atmosphere retail packaging systems. While injection of non-meat ingredients is a traditional method of impacting the aforementioned attributes, the combination of blade tenderization and vacuum-tumbling could potentially help reduce package purge and improve tenderness while not negatively impacting beef color, juici-ness or flavor. Our objective was to evaluate the effects of non-meat ingredients, blade tenderization and vacuum tumbling on the textural, visual and sensory characteristics of steaks from Biceps femoris, Triceps brachii long head, Supraspinatus and Longissimus dorsi muscles packaged in a high oxygen, modified atmosphere retail package. Muscles were assigned to one of 24 treatments: control, injection (injected or non-injected), blade tenderization (0, 1 or 2 passes)and vacuum tumbling (0, 5, 10 or 20 minutes). In-jected muscles contained up to 10% of brine containing water and 1.55% potassium lactate, 0.1% sodium diacetate, 0.3% sodium tripolyphosphate and 0.4% salt in the final product. After injection, the muscles were vacuum tumbled and then blade tenderized sequentially. Steaks sliced from the muscles were stored in high oxygen (80% O2, 20% CO2)modified atmosphere packaging for 1, 3, 7, 10 or 14 days at 2ºC. Steaks were evaluated for purge (%), Warner-Bratzler shear force (kg), CIE Minolta color space values (L*, a*, b*), trained meat descriptive attribute color panel, cook yield (%)and pH on each storage day. A trained meat de-scriptive attribute sensory panel evaluated steaks on day 1 only. Injected Biceps femoris and Supraspinatu} steaks had less purge (P 0.05), lower Warner-Bratzler shear force val-ues (P 0.05) and were darker in color (P 0.05) than non-injected steaks. Injection improved muscle fiber tenderness (P 0.01) and overall tenderness (P 0.01). Injected steaks had higher flavor intensity (P 0.01); higher salt (P 0.01) and bitter basic tastes (P 0.01); and higher chemical flavor aro-matic (P 0.05) compared to non-injected treatments. Blade tenderized Biceps femoris and Supraspinatus had higher cook loss (P 0.05). Blade tenderization decreased Warner-Bratzler shear force values (P 0.05) in the Supraspinatus, but not Biceps femoris. However, blade tenderization de-creased purge (P 0.05) in the Biceps femoris. Injection of non-meat ingredients can improve the tenderness of high connective tissue cuts of beef. Key Words: Beef, Non-meat Ingredients, High Connective Tissue


Food Safety

MICROBIAL CHARACTERISTICS OF BEEF TOP BUTTS STORED AT DIFFERENT TEMPERATURE SCENARIOS DURING AGING J. M. Behrends, J. W. Savell, G. R. Acuff e-mail: [email protected] Texas A&M University, College Station, TX Restaurants and food services continue to utilize aging as a process to improve tenderness and increase palatability of beef. The process may include initially aging subprimals for 2 to 3 weeks followed by an additional aging period for steaks during distribution and storage before cooking and serving. We evaluated four scenarios to determine the im-pact of storage refrigeration temperatures on lactic acid bac-teria and aerobic bacteria populations on top butts (m. glu-teus medius; TB) and steaks during aging. The temperature parameters for TB subprimals were -1ºC (TBLow) and 4.5ºC (TBHigh) for 26 days followed by cutting into steaks with additional 13 days of aging at these temperature treatments: 2 days at -1ºC; 4 days at 1.5ºC; 7 days at 4.5ºC (STLow) and 2 days at 4.5ºC; 4 days at 1.5ºC; 7 days at 7ºC (STHigh). The four scenarios included TBLow/STLow; TBLow/STHigh; TBHigh/STHigh; TBHigh/STLow. Three TB were obtained for each of the two storage temperatures (-1ºC and 4.5ºC) and three evaluation days (initial, 13, and 26; n=18 top butts total). Excised samples (10 cm 2 surface area � 1mm deep) were removed on each of the TB according to their assigned aging day and assessed for microbial populations. On d 26, TB were cut into 6 steaks each (n=54 TB steaks) and vacuum packaged: 3 steaks from each TB were ran-domly allotted to low temperature parameters and 3 were randomly allotted to high temperature parameters for an additional 13-d storage time and were evaluated for micro-bial populations on three days (27 d, 33 d, and 40 d total aging time). Product stored at all four scenarios reached aerobic bacteria populations of questionable acceptability (>6 log10/cm 2). Initial populations were relatively low, however, increasing numbers of anaerobic bacteria and lactic acid bacteria populations indicate growth during stor-age despite the different treatment groups applied. The aerobic populations tended (P = 0.07) to be lower for TBLow versus TBHigh. There was a significant increase in aerobic populations from day 1 to 13 for top butt subpri-mals. Also, there was an increase in aerobic populations for steaks from day 27 to 33. Top butt steaks from TBLow were

significantly lower in aerobic bacteria populations versus those from TBHigh. Interaction for treatment � day was not significant for aerobic bacteria populations. The TBHigh subprimals displayed higher lactic acid bacteria populations than TBLow subprimals (P <0.05). There was an increase in lactic acid bacteria populations from day 1 to 13. In addi-tion, TBLow subprimals had steaks that were significantly lower in lactic acid bacteria populations than TBHigh sub-primals. There was an increase in lactic acid bacteria popu-lations from day 27 to 33. Samples that were aged using TBLow/STLow and TBLow/STHigh treatments displayed lower lactic acid bacteria populations than TBHigh/STHigh and TBHigh/STLow treatments. This study shows that con-trol of the temperatures during the initial aging stage is es-sential to control the microbial populations on top butts. There is need to assess any off odors, as well as any off fla-vors that may be attributed to the microbial growth during the aging process. Key Words: Beef, Aging, Food Safety COST ANALYSIS OF IRRADIATING BONELESS SLICED HAM F. Cordona, P. D. O'Rourke, B. R. Wiegand e-mail: [email protected] Illinois State University The objective of this study was to estimate production costs for sliced boneless ham. Data were collected on the cost structure of irradiation of meat products by interviewing personnel at firms providing irradiation equipment and ser-vices to firms producing processed pork products. A com-puter simulation was developed based on these data and an estimate of potential profitability was made for irradiation of sliced boneless ham using three mutually exclusive scenar-ios. The simulation used a model that included net present value, internal rate of return, break-even point and unit costs for four rates of throughput under the three scenarios. The scenarios included irradiation using X-ray, irradiation using Cobalt-60 and irradiation by contracting the irradia-tion services. The four rates of throughput were 50, 100, 150, and 250 million pounds annually. Based on the simu-lation results, it is evident that profit can be attained in each of the three scenarios. However, these profits are dependent on annual throughput of the facility. X-ray irradiation was profitable at volumes over 51 million pounds annually. Co-balt-60 irradiation showed the greatest profitability with an internal rate of return almost twice that of capital cost. Con-tracting irradiation services was advisable for volumes of




150 million pounds or more annually because irradiation and transportation charges combined would exceed net income before interest and tax for lesser volumes. Total costs per pound ranged from $0.04 (50 million pounds) to $0.01 (200 million pounds) for X-ray, $0.02 (50 million pounds) to $0.008 (200 million pounds) for Cobalt-60, and $0.06 (50 million pounds) to $0.05 (200 million pounds) for contracting irradiation services. The rate of return ranged from 15% to 71% for X-ray, 27% to 100% for Cobalt-60, and up to 196% for contracting irradiation services. These results indicate that based on specific assumptions, opera-tion of and/or contracting of irradiation facilities is a profit-able enterprise and is dependent on annual throughput vol-ume. Key Words: Ham, Irradiation, Cost Analysis A MICROBIOLOGICAL PROFILE OF RED MEAT CARCASSES PROCESSED IN VERY SMALL ESTABLISHMENTS IN THREE GEOGRAPHICAL REGIONS OF THE UNITED STATES 1S. L. Flowers, 2M. Costello, 2P. M. Gray, 2D. Kang, 3M. M. Brashears, 3A. Echeverry, 3J. E. Mann, 1W. R. Henning, 1E. W. Mills, 1C. N. Cutter e-mail: [email protected] 1The Pennsylvania State University, 2Washington State Uni-versity, 3Texas Tech University A total of 866 red meat carcasses were sampled in very small meat establishments in four states (Pennsylvania, Washington, Idaho, and Texas) from July 2002 to March 2003 to establish a baseline for carcass hygiene and the prevalence of foodborne pathogens. Carcasses were asepti-cally swabbed using the U. S. D. A. 3-site sponge sampling method after the final rinse step during primary processing or after 48 h of chilling. Generic E. coli, total coliform and mesophilic aerobic plate counts (APC) were determined with Petrifilm # and the presence or absence of Salmonella spp., E. coli O157:H7, and Campylobacter spp. by appro-priate enrichment and culture methods. Colonies that were presumptively identified as positive for pathogens were con-firmed by latex agglutination or polymerase chain reaction, as suitable. Mean microbial loads for all carcasses were 3.86 log10 CFU/ml for generic E. coli, 3.86 log10 CFU/ml for coliforms, and 6.38 log10 CFU/ml for APC. APC did not differ substantially among species. Lamb carcasses con-tained significantly greater (P <0.01) loads of generic E. coli (4.64 log10 CFU/ml) and coliforms than beef and pork. No distinctions in generic E. coli or coliform counts were evi-dent among the two veal types, beef, or pork. Pathogens were not detected on special-fed veal (n = 28) or chevon (n = 1). Salmonella spp. were present on 0.39% (2/519) of beef, 1.96% (3/153) of pork, 0.74% (1/136) of lamb, and 13.79% (4/29) of bob veal carcasses with an overall pres-ence of 1.15% (10/866). Though not isolated from beef, four pork (2.61%), two lamb (1.47%), and six bob veal (20.69%) carcasses were contaminated with E. coli O157:H7 for an overall prevalence of 1.39%. Bob veal

(41.38%) and lamb samples (17.65%) contained Campylo-bacter spp. along with 6.54% of pork and 0.39% of beef swabs for an overall prevalence of 5.54%. Future research will investigate the effectiveness of a variety of antimicro-bial rinses on the reduction of bacterial loads on carcass surfaces. This information will be transferred to very small meat establishments to assist with carcass decontamination methods. Key Words: antimicrobial interventions, very small estab-lishments, baseline RELATIONSHIP BETWEEN AEROSOLIZED MICROBIAL LOAD AND CONTAMINATION OF FULLY COOKED THEN FROZEN MEAT PRODUCTS 1A.A. Helm, 1C.R. Kerth, 1W.R. Jones, 1T.A. McCaskey, 1D.E. Conner e-mail: [email protected] 1Auburn University Air has long been thought to be a potential source of mi-crobial contamination. Recently, research has shown that microbial organisms, including pathogenic bacteria, have been found in significant numbers in air. The objective of this research was to determine relationships between the microbial concentration in air and the level of contamina-tion of fully cooked meat products. Air in a commercial processing facility was sampled (n=113) for microbiological organisms during a 5-month period by using an EM MAS-100 Eco air monitoring system with plate count agar. Air was sampled for 5 minutes 2-4 times per day in 45-minute intervals in the packaging area at either next to the con-veyor, where product is exposed to air, or in the area of highest employee traffic and expressed as log cfu/500L of air. Product samples were collected in 15-minute intervals to accumulate a 3 sample composite every 45 minutes, which corresponded to each air-sampling period. Serially diluted product samples and air samples were incubated at 37ºC for 24 h or 48 h. Twenty-four hour air counts ranged from 0.15 to 2.54 log cfu/500L, with a mean of 1.25 log cfu/500L, and 48 hour counts ranged from 0.30 to 2.54 log cfu/500L, with a mean of 1.65 log cfu/500L. Product counts ranged from 0.30 to 2.9 log cfu/g at 24 hours and from 0.30 to 3.78 log cfu/g at 48h, with means of 1.60 log cfu/g and 1.9 log cfu/g for 24 h and 48 h respectively. No correlations existed between 24 or 48 h air counts at either the conveyor or traffic areas and 24 or 48 h product counts (P >0.05). Simple regression found at most 9.4% of the variation in air counts was accounted for by times doors were opened. Multiple regression models showed that opening of doors, wind velocity at the area of highest employee traffic, wind velocity at the conveyor, and time of day accounted for 21% of the variation in air quality, and day of year, outside temperature, times doors were opened, number of employ-ees, and freezer conveyor speed described 34% of the variation in product contamination. These data indicate that no direct relationship exists between microbial air quality and product contamination, but environmental conditions


may account for up to one-fifth of the variation in air con-tamination and one-third of the variation in product con-tamination. Key Words: Air Quality, Microbial Contamination, Fully Cooked Product CONSUMABLE HOUSEHOLD PRODUCTS USED FOR DECONTAMINATING RETAIL PORK LOIN CHOPS Lisa McKee, Lori Neish, Nancy Flores e-mail: [email protected] New Mexico State University As awareness of foodborne illness has increased, efforts have been made to reduce contamination of raw meats. Rinsing or spraying carcasses with water, organic acids and other substances have been investigated on a commercial scale as a means of reducing microbial loads. This study focused on consumer rinsing methods to decontaminate raw pork loin chops at home. Ten common consumable products (apple juice, cranberry juice, orange juice, dis-tilled white vinegar, Coca-Cola™, 2% lowfat milk, clam juice, 10% sodium bicarbonate solution, 10% sodium chlo-ride solution and tap water) were used as rinsing agents to decontaminate raw pork loin chops. All samples were evaluated for total aerobic plate (APC), total coliform and Escherichia coli ( E. coli) counts before and after rinsing us-ing a swab method and standard procedures for Petrifilm™ plates. Total coliforms and E. coli counts were below de-tectable levels both before and after rinsing. No differences (p=0.7061) in before rinsing APC were detected. Before rinsing counts ranged from 4.09 to 4.74 logs. After rinsing APC for vinegar treated chops (2.26 logs) was lower (p 0.0052) than after rinsing APC for all other treatments. No differences (p 0.1138) were detected between the remaining treatments. All treatments reduced bacterial loads, but vine-gar seemed to be the most effective rinsing agent under the study conditions. Additional rinsing agents and exposure time of the rinsing agents are currently being studied. Key Words: Pork, Rinsing, Consumer DESTRUCTION OF NON-PATHOGENIC ESCHERICHIA COLI IN BEEF JERKY MADE WITH HOME-STYLE DEHYDRATORS S.R. Pohlman, N. Kalchayanand, W.J. Means, R.A. Field, A.W. Wolf e-mail: [email protected] Univeristy of Wyoming Laramie WY USA Association of jerky products, made in the home by tradi-tional drying methods, with foodborne disease has raised questions about their safety. Our objectives were to deter-mine 1) consumer acceptance of beef jerky made with an-timicrobial ingredients, and 2) destruction of non-pathogenic Escherichia coli in beef jerky processed in home-style dehydrators. Four recipes were developed using ingredients with known antimicrobial properties. Recipes

consisted of the following as percent of the meat block: 2% salt, 1.25% sugar, 0.4% ground black pepper, 0.33% garlic powder (S); 2.91% Morton’s Tender Quick ®, 0.77% sugar, 0.4% ground black pepper, 0.33% garlic powder (CS); S with 17% red wine vinegar (SV); and CS with 17% red wine vinegar (CSV). Chemical and physical analyses, as well as a consumer acceptance evaluation, were performed on jerky produced from the four recipes. Time/temperature perform-ance of four dehydrator models readily available to con-sumers was recorded while drying full loads of beef jerky. Two recipes (CS & CSV), based on consumer evaluation results, and two dehydrators, based on time/temperature performance, were selected to test beef jerky inoculated with Escherichia coli NCSM. Inoculated (6.3 to7.4 log cfu) and non-inoculated control meat strips were surface plated on plate count agar containing 1% glucose (PCA) and violet red bile agar (VRBA) at selected stages of jerky production. Bacterial populations of inoculated CS strips were reduced (P<0.01) by 0.7 log on VRBA after refrigeration (~8ºC, 14 h). Addition of vinegar (CSV) caused a greater reduction (1.7 log, P<0.01) on VRBA after refrigeration. Post drying, inoculated CS bacterial populations were reduced by 4.8 log (P<0.01) and 5.3 log (P<0.01) on PCA and VRBA, re-spectively. Using CSV, each dehydrator achieved greater than 6.0 log reduction of E. coli NCSM in the final product (P<0.01). CSV and overnight refrigeration can effectively control E. coli NCSM in beef jerky dried in home-style de-hydrators that reach 66ºC during drying. Key Words: E. coli, Jerkey, Beef EFFECTS OF VACUUM TUMBLING ON Salmonella MIGRATION INTO THE INTERIOR OF INTACT, MARINATED TURKEY BREASTS C.R. Warsow, B.P. Marks, E.T. Ryser, A. Orta-Ramirez, A.M. Booren e-mail: [email protected] Michigan State University East Lansing, MI 48824 Vacuum tumbling with a phosphate marinade is a common method used to increase the juiciness and infuse flavors into whole-muscle roasts. As marinade infiltration is enhanced, there may be potential for migration of surface bacteria into the inner portions of the muscle, which are believed to be sterile. Penetration of bacteria to the interior of meat using invasive tenderization techniques has been studied; how-ever, the incursion of surface pathogens, like Salmonella, during vacuum tumbling with a marinade has not been tested. Therefore, the objective of our study was to quantita-tively determine the migration of Salmonella into whole muscle turkey breasts during vacuum tumbling. Initially, a study was conducted to determine the extent of unidirec-tional penetration of Salmonella in turkey breast muscle when exposed to vacuum. Irradiated turkey breast (10L x 10W x 5H cm) was placed in a marinade (salt, mixed phos-phate, and water) containing 10 8 CFU/ml of a cocktail of Salmonella, and exposed to vacuum (101.3 kPa) for various times (0, 5, 10, 20 min). Samples were removed aseptically


by coring vertically with a 1.27 cm diameter Warner-Bratzler hand corer. The cores were sectioned into 1 cm segments, macerated in buffered peptone water and enu-merated on aerobic Petrifilms®. Salmonella counts de-creased (P<0.001) with depth below the inoculated surface and increased (P<0.001) with application of the vacuum. Although these tests did not exactly mimic a commercial process, they did demonstrate that significant migration could occur into whole-muscle product during marination, even without any mechanical action. Subsequently, using two different techniques, tissue samples were excised asep-tically from the inner portions of a whole turkey breast after marination with a Salmonella-inoculated marinade. Com-bined, these methods examined Salmonella multidirectional penetration when the entire muscle was subjected to vac-uum tumbling. In one study the muscle was vacuum tum-bled with the marinade for various durations (5, 10, 20 min). In a separate experiment, whole breast was exposed for 20 min to the following treatments: (1) vacuum tum-bling, (2) tumbling without vacuum, (3) vacuum without tumbling, and (4) still marination (control). Results con-firmed significant (P<0.001) migration of Salmonella into the samples during marination. Additionally, both vacuum and tumbling resulted in greater (P<0.05) Salmonella counts inside the samples, as compared to the inoculated control. Pathogens on or below the surface of whole meat products need to be inactivated as part of any commercial cooking process. Salmonella penetration may need to be integrated into microbial inactivation models to accurately determine the fate of pathogens during further processing of whole muscle products. Key Words: Vacuum Tumbling, Salmonella, Turkey ESCHERICHIA COLI O157:H7 DESTRUCTION IN FRANKFURTERS USING HYDROSTATIC PRESSURE AND BACTERIOCINS A.W. Wolf, S. Bandyopadhyaay, N. Kalchayanand, B. Ray, W.J. Means e-mail: [email protected] Univeristy of Wyoming Laramie WY USA Escherichia coli O157:H7 has cost the food industry 270 million dollars a year from 1992-2002. High hydrostatic pressure (HHP) is a non-thermal processing technique used to control pathogens. Our goal was to determine if HHP, in conjunction with bacteriocins of lactic acid bacteria, could destroy E. coli O157:H7 in vacuum-packaged frankfurters. Bacteriocins were produced by fermentation and purifica-tion. After purification, bacteriocin mixture (BMIX) was made consisting of 2500 au nisin and 2500 au pediocin. Seven strains of E. coli O157:H7 were grown to early sta-tionary phase and subjected to 345 MPa for 5 min at 25ºC (HHP34525) or 345 MPa for 5 min at 50ºC (HHP345 50). Five relatively pressure-resistant strains were selected and mixed in an equal-ratio cocktail. Cocktail mixtures were treated with HHP34550 with or without BMIX. Survivors were enumerated by pour plating on TSY agar and incubat-

ing at 37ºC for 48 h. Because preliminary data indicated HHP34550 would not be sufficient for destruction of E. coli O157:H7 even in conjunction with BMIX, treatments were increased to 414 MPa for 5 min at 50ºC (HHP41450) for the inoculation study. Twenty-eight packs of two 27 g frankfurt-ers were inoculated with 6 log/ml of cocktail and subjected to HHP41450or HHP41450+BMIX. Survivors were enu-merated by pour plating on TSY and VRBA agars and incu-bating 48 h at 37ºC. In 6 log-inoculated packs, HHP41450 resulted in 2.4 and 4.6 log reduction on TSY and VRBA, respectively; while HHP41450+BMIX resulted in a 5.7 and 5.9 log reduction on TSY and VRBA, respectively. HHP (414 MPa, 50ºC for 5 min), alone was insufficient to destroy E. coli O157:H7 in frankfurter packs. However, an impor-tant synergistic effect was observed using HHP in conjunc-tion with bacteriocins of lactic acid bacteria, postulated to be due to changes in cell membrane morphology during pressurization. This combination of treatments effectively destroyed E. coli O157:H7 in inoculated frankfurters. Key Words: Escherichia coli O157:H7, Hydrostatic Pressure, Pediocin, Nisin


Education

KNOWLEDGE, ATTITUDES, AND BEHAVIOR RELATED TO GAME HANDLING PRACTICES IN NORTH DAKOTA DEER AND ELK HUNTERS J. A. Garden-Robinson, M. J. Marchello, C. S. Stoltenow, G. P. Lardy, D. J. Klenow, D. D. Hulse e-mail: [email protected] North Dakota State University Resident and non-resident hunters spent $166.4 million on hunting activities in North Dakota (ND) in 2001, an amount generating an additional $199 million in secondary eco-nomic effects, for a gross business volume of $365.4 mil-lion. Nineteen percent of North Dakotans ages 16 and older hunted in 2001. This study of ND deer and elk hunters’ practices and perceptions included a series of focus groups and separate 10-minute telephone surveys to a random sampling of 267 successful deer hunters and all successful elk hunters (n = 30). Results indicate a need for improved handling and preparation procedures. Several differences between deer and elk hunters with respect to processing and choices of finished products were apparent. Sixty-eight percent of deer hunters processed their own animals at home, while 45% of elk hunters did so. Ninety percent of the deer hunters made sausage out of at least a portion of their venison, 60% made use of fresh chops, steaks or roasts, and 48% prepared ground venison. Nearly all of the elk hunters (97%) made use of fresh chops, steaks or roasts. Ninety percent made ground elk, and 48% made sausage. Less than 13% of deer and elk hunters reported eating any organ meats, such as hearts and livers. Two deer hunters reported eating brain. While 76% of deer hunters and 90% of elk hunters reported owning a meat thermometer, only 5% of deer hunters and 16% of elk hunters who prepared fresh roasts reported using a thermometer to test for done-ness. Only 6% of deer hunters and 13% of elk hunters who made sausage said they used thermometers to check inter-nal temperature of the cooked product. While the low fre-quency of thermometer use is problematic for all types of meat products, the lack of use for sausage and other ground meat poses the most significant health threat. Almost all the deer and elk hunters reported eating meat from the animals they had harvested. In addition, more than 90% of both hunting groups reported that family members also con-sumed the meat. Sixty-three percent of deer hunters also shared their meat with relatives and friends; whereas, 90%

of elk hunters shared meat products. Regarding knowledge of chronic wasting disease (CWD), 29% of deer hunters and 52% of elk hunters rated themselves knowledgeable or highly knowledgeable about the disease. More than 57% of deer hunters expressed little or very little concern about CWD. Elk hunters offered mixed responses, with more than half reporting little concern; while 25% indicated a high level of concern. Despite concern about CWD, 76% of deer hunters and 84% of elk hunters haven’t changed their han-dling practices in response to CWD. Survey responses indi-cated the most effective means of informing ND deer and elk hunters was through brochures mailed with hunting licenses. Magazines, radio, and television were also rated highly effective. The results of this survey indicate the need for improved educational efforts in the area of wild game handling and preparation procedures to prevent possible outbreaks of food-borne illness Key Words: Hunters, Attitudes, Handling



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