15. D. D. Pless and W. J. Lennarz, Proc. Natl.Acad. Sci. U.S.A. 74, 134 (1977).

16. R. B. Trimble and F. Maley, J. Biol. Chem. 252,4409 (1977).

17. B. Foltmann, Methods Enzynol. 19, 421 (1970).18. R. A. Smith and T. Gill, J. Cell. Biochem.

(suppl. 9C), 157 (1985).19. , in preparation.20. R. J. Summers and S. Roof, personal communi-

cation.21. J. B. Hicks, A. Hinnen, G. R. Fink, Cold Spring

Harbor Symp. Quant. Biol. 43, 1305 (1979).22. J. M. Schoemaker, A. H. Brasnett, F. A. 0.

Marston, EMBO J. 4, 775 (1985).23. S. D. Emr, V. A. Bankaitis, J. M. Garrett, M. G.

Douglas, in Protein Transport and Secretion,M.-J. Gething, Ed. (Cold Spring Harbor Labora-tory, Cold Spring Harbor, N.Y., 1985), p. 184; J.H. Rothman et al., ibid., p. 190. Complementa-tion tests show that the vpt3 and vpt5 mutants ofEmr are different from sscl and ssc2.

V

The use of biotechnology in the manu-facture of food and beverages has beenpracticed for more than 8000 years withvinegar, alcoholic beverages, sour-dough, and cheese production being the

24. M. Carlson, R. Taussig, S. Kustu, D. Botstein,Mol. Cell. Riod. 3, 439 (1983).

25. J. Kuwjan and I. Herskowitz, Cell 311, 933 (1982).26. k. Arima et al., Nucleic Acids Res. 11, 1657

(19"3).27. T. Alber and G. Kawasaki, J. Mol. Appl. Genet.

1,419 (1982).28. M. Carlson and 1). Botstein, Cell 28, 145 (1982).29. M. Rose and D. Botstein, J. Mol. Biol. 170, 883

(1983).30. H. Towbin, T. Staehelin, J. Gordon, Proc. Nail.

Acad. Sci. U.S.A. 76, 4350 (1979).31. YNB contained, per liter: 7 g of yeast nitrogen

base (Difco), 20 g ofglucose or galactose, and 20g of agar (when used in plates). Detection ofactive chymosin required the addition of bovineserum albumin (25 pg/ml) to liqiuid medium butnot to agar plates. Acid activation was unneces-sary, except when succinate-buffered YNB(YNB buffered atpH 6 with 10 g of succinic acidand 6 g of NaOH per liter) was used, in that

tissue culture systems, and bioengineer-ing offer great potential for application toseveral areas of food production andprocessing. A key question related tothis issue is, what are the constraints

Summary. The food processing industry is the oldest and largest industry usingbiotechnological processes. Further development of food products and processesbased on biotechnology depends upon the improvement of existing processes, suchas fermentation, immobilized biocatalyst technology, and production of additives andprocessing aids, as well as the development of new opportunities for food biotechnol-ogy. Improvements are needed in the characterization, safety, and quality control offood materials, in processing methods, in waste conversion and utilization processes,and in currently used food microorganism and tissue culture systems. Also neededare fundamental studies of the structure-function relationship of food materials and ofthe cell physiology and biochemistry of raw materials.

most prominent examples (1). Biotech-nological processes are now being usedto produce other fermented products,food and feed additives, and processingaids (Table 1). In fact, the food process-ing industry, which has annual sales of$300 billion in the United States andabout £30 billion in Great Britain, is theoldest and largest user of biotechnologi-cal processes (2).An important issue today is the impact

that modem biology will have on thefood industry. Recent advances in mo-lecular biology, fermentation science,

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hindering applications of biotechnologyto the food industry? In this article, weattempt to address these points and toreview the current role of biotechnologyin the production and processing offood.

Biotechnology in Food Production

Biotechnology can significantly influ-ence the food supply, including the pro-duction and preservation of raw materi-als and the alteration of their nutritionaland functional properties. In addition,

yeast meabolism reduces the pH of the mediumto levels sufficient to activate all the prochymo-sin produced.

32. K. Strh, D. T. Stinchcomb, S. Scherer, R. W.Davis, Proc. Natl. Acad. Sci. U.S.A. 76, 1035(1979).

33. We thank T. Gill and K. Stashenko whose workwas vital to the success of this project. We aregrateful for key contributions from the followingpeople at Collaborative Research, Inc.: J. Mao,T. Kohno, E. Yamasaki, M. E. Rhinehart, R.Knowlton, V. Brown, S. Porteous, and C. Still-man. We thank R. J. Summers and S. Roof ofDow Chemical Company for unpublished yeastfermentation results. Purified native calf pro-chymosin and rabbit antiserum directed againstcalf chymosin were gifts from R. Goltz of DowChemical Company. We thank G. Fink and G.Vovis for critically reading the manuscript. Thiswork was partially supported by a contract withDow Chemical Company.

development of production aids, pro-cessing aids, and direct additives such asenzymes, flavors, polysaccharides, pig-ments, and antioxidants can improve theoverall utilization of raw materials.Raw materials. Plant products derived

from fewer than 30 plant species providemore than 90 perceht of the human diet.Eight cereal crops supply more than halfthe world's calories (4). Animal productscontribute over 56 million tons of edibleprotein and over 1 billion megacaloriesof energy annually (5). In addition, theincreasing importance of marine foodproducts and single cell proteins (SCP)as raw materials has been stressed (6).

Currenily, the role of biotechnology inraw material production is directed to-ward (i) increasing productivity throughimproved efficiency of nutrient use andconversion, (ii) increasing productivitythrough improved plant resistance, and(iii) identifying new food sources withdesirable properties.Feed efficiency and productivity of

animals has been increased substantially(7). Furthermore,CP, derived from thedried cells of microorganisms for use asprotein sources in human food and ani-mal feeds, are cultivated on a large scaleby using both photosynthetic and non-photosynthetic microorganisms (8). Ex-tensive work is under way to increasethe ability of plants to fix atmos0hericnitrogen for their metabolic use 49, andcultured plants and plant cells are beingconsidered for food production (10).

Additional efforts include the genetic

Dietrich Knorr is professor offood processing andbiotechnology, Biotechnology Group, Departmentof Food Science, University of Delaware, Newark19716. Anthony J. Sinskey is professor of appliedmicrobiology, Department of Applied Biological Sci-ences, Massachusetts Institute of Technology, Cam-bridge 02139. This article was adapted from a posi-tion paper presented at the Institute of Food Tech-nologists workshop on research needs, 11 to 14lJq'ember 1984,-Arlington Heights, Mllinois, andfrdm a subsequently developed document on re-search needs in food biotechnology.

SCIENCE, VOL. 229

Biotechnology in FoodProduction and Processing

Dietrich Knorr and Anthony J. Sinskey

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Table 1. World production, market value, and end use of selected products of the biotechnology-based food industry (3).

Production Market size(metric tons per year) (millions U.S. $)

Products Primary end use1974 1981 1974 1981 199( )(estimated)

Amino acids 455 x 103* 290 1.9 x 103t 2.2 x 103t Feed additive, food enrich-1.8 x 103* ment and flavoring agent,

feed preservativeCitric acid 265 x 103 300 x 103t Food additive, processing aidEnzymes 65 x 103 132 310 to 400 1.5 x 103 Processing aidVitamins 668t Feed and food additive, food

1.1 x 103 enrichment agentBaker's yeast 0.97 x 106 1.75 x 106t 380 Food additive, enrichment

agentBeer 75 x 106 87 x 106t 27 x 103§* 44X 103§ BeverageCheese 11 x 106 12 x 106 FoodFermented foods 3.5 x 103 6 x 103 FoodMisoll 5.72 x 103 FoodSoy saucell 1.18 x 106* Food

*Data for 1982. tData for 1979. tFermented chemicals. §Alcoholic beverages. IIJapan only.

improvement of animal breeds; improve-ments in, the reproductive efficiency oflivestock; the use of vaccines and mono-clonal antibodies in the diagnosis, pre-vention, and control of animal diseases;and the improvement of crop speciesthrough the regulation of endogenousgenes, the transfer of DNA from onespecies to another (for example, fusionof cells, transfer of subcellular organ-elles, vector-mediated t)NA transfer),the improvement of plant resistance fac-tors (for example, plant and microbialproduced pesticides), and the improve-ment of photosynthetic efficiency (7, 9,11). In addition, the use of the geneticdiversity in plants, new plant and animalfood sources, and improved food pro-duction technologies (such as aquacul-ture, hydroponics, continuous tissue cul-ture, and solid-state fermentation) arebeing sought continuously (9, 10, 12).Raw material modification and im-

provement can be applied to convert rawmaterials, to increase stress resistance,and to improve their functionality andnutritional quality.

In the processing of raw materials forfood, polymeric carbohydrates may beremoved, included in the product as di-etary fiber, or converted to other prod-ucts, such as sugars. The ability to con-vert these polysaccharides and to impartspecific structural changes can result inimprovements in the functionality of car-bohydrates in foods and in 'increases inproduct yields (12). In vitro selection hasbeen applied to improve the salt and coldtolerance and the herbicide and droughtresistance of crop' plants. Work on theimprovement of such functional proper-ties as color, flavor, and texture of rawmaterials is be'ing conducted, as is workon increasing the essential nutrients and20 SEPTEMBER 1985

reducing the undesirable constituents inraw materials (13).Raw material preservation by biologi-

cal processes is critical to agriculture andthe food processing industry. The pro-duction of silage, the fermentation ofcocoa and coffee beans, the "fermenta-tion" (oxidation) of tea leaves, and theconversion of raw material into SCP orfeedstock chemicals (1, 14) suggest thediversity and magnitude of microbial fer-mentation processes applied for raw ma-terial preservation and quality improve-ment (1, 14).Additives and productionlprocessing

aids. Additives and production aids usedin raw material production include suchmaterials as vaccines and growth regula-tors in animal production and microbialinsecticides and herbicides in plant pro-duction, and they all are subject to inten-sive investigation (11, 15). Historically,such food additives as fatty acids andother organic acids, vanilla (for flavor),and vitamins B2, B12, C, and D havebeen produced through biotechnologicalprocesses. Intensive work is now beingcarried out on the production of plantmetabolites by tissue culture, includingflavors, pigments, vitamins, enzymes,antioxidants, antimicrobials, and lipidsand on the microbial production of fla-vors, pigments, vitamins, amino acids,antioxidants, biosurfactants, and poly-saccharides (16). For example, the plantmetabolite shikonin, a bright red naph-thaquinonine compound used as a dyeand as an antibacterial and anti-inflam-matory agent, is currently produced onan industrial scale from cultured Litho-spermum erythrorhizon cells (17). Blue-green algae that produce tocopherolshave been isolated, and a potential vita-min E precursor has been found in vari-

ous genera of bacteria and yeasts. Thissuggests the potential for the develop-ment of a one-step fermentation processto fulfill the demand for vitamin E (18).Aspartame (L-aspartyl L-phenylala-

nine methyl ester) is a low-calorie dipep-tide sweetener that has recently beenapproved as a food additive. Precursorssuch as aspartic acid and phenylalanineare produced by fermentation processes,and the microbial production of the di-peptide aspartyl-phenylalanine has beenperformed at the laboratory level byrecombinant DNA processes. World-wide demands for L-phenylalanine areprojected to increase from 50 metrictons in 1981 to 7900 metric tons in 1990(19).Improved processes for the produc-

tion of other amino acids, such as L-lysine and L-threonine, have been devel-oped recently (20).

Polysaccharides commonly derivedfr6m algae or botanical sources and usedas functional agents are now being pro-duced commercially through microbio-logical processes. The search for newmicrobial polysaccharides is an area ofactive research. Recent advances towardunderstanding the specific steps in-volved in the biosynthesis of specificpolysaccharides offer promise for thecontrol and manipulation of the structureand form of the final polysaccharideproduct (21). There are a number offood-related applications of polysaccha-rides; they include the microencapsula-tion of flavors, immobilization of en-zymes, entrapment of whole cells, andaiding of flocculation in food processwaste management (22).

Yeasts have been used traditionally inthe production of alcoholic beverages,and attention recently has been given to

1225

the genetic manipulation ofSaccharomy-ces yeast cells to increase the efficiencyof the brewing process and to preparelow-calorie, or so-called light, beers.Currently, glucoamylase enzymes frommicrobial sources (for example, Asper-gillus niger and Aspergillus awamori) areused in the production of many lightbeers. These enzymes are fairly thermo-stable and are not destroyed by normalbeer pasteurization at 600 to 62°C, so thebeers become sweeter upon storage ow-ing to the release of glucose units fromdextrins by the glucoamylase. Thus, theproduction of a thermosensitive gluco-amylase by a brewer's yeast could be ofsignificant value (23).Enzymes are used extensively in food

production and processing. The onesmost widely applied are amylases, glu-cose oxidases, proteases, pectic en-zymes, and lipases. Excellent reviews onthe production and utilization of foodenzymes are available (24). Immobilizedenzymes and immobilized whole cellshave received significant attention asvaluable biocatalysts for the food pro-cessing industry (25). The advantages ofthe application of immobilized systemsinclude continuous operation, reuse ofthe biocatalyst, ease of process control,improved biocatalyst stability, and re-duced waste disposal problems (26).

Immobilized biocatalyst technologyalso can be applied successfully to theproduction of secondary plant metabo-lites (27). In addition, the production ofenzymes with enhanced stability to tem-perature and other processing conditionsis receiving much attention (28).The significant impact that biotechnol-

ogy can have on the production of a foodingredient is exemplified by the develop-ment of high-fructose corn syrup(HFCS) technology. The production ofHFCS involves the application of twoamylases and glucose isomerase to effectthe liquification and subsequent sacchar-ification of cornstarch to yield an ap-proximately equimolecular mixture offructose and glucose. Because fructoseis sweeter than glucose, HFCS is aboutas sweet as a sucrose syrup of the samesolids content, and it has found wide usein processed foods. About 2.5 millionmetric tons of HFCS (dry basis) wereproduced in 1981, compared to about72,000 metric tons in 1976. Over a 10-year period (1970 to 1980), HFCS in-creased its share of U.S. per capita con-sumption of nutritive sweeteners fromalmost nonexistence to 16.4 percent,while sucrose usage decreased from 84.1percent to 68.0 percent (2, 25). The pro-duction of HFCS through the use of

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enzyme technology is one of the greatestcommercial successes of immobilizedbiocatalyst technology (29).Production methods. With the avail-

ability of high-performance bioreactorsfor large-scale fermentation processes(30), current emphasis is on computerprocess control, although there is still aneed to improve bioreactor performanceby overcoming the limitations of heatand mass transfer (31). This is especiallyimportant with new biocatalysts and thescale-up of such processes as animal andplant cell culture systems (32). The engi-neering problems are especially chal-lenging when non-Newtonian systemsare involved (33).

Extensive work on immobilizationtechniques, reactor design, and cellmembrane permeabilization will help toovercome the current problems in con-tinuous animal and plant cell cultures;these problems include shear sensitivity,slow growth rates, and the intracellularstorage of metabolites (34).

Biotechnology in Food Processing

Biotechnology in food processing cansignificantly affect food product compo-sition, quality, and functionality by pro-viding tools for product modification,preservation, and stabilization, as wellas for safety, characterization, and quali-ty control. In addition, processing meth-ods, especially separation and fermenta-tion processes and waste treatment andutilization can contribute to the improve-ment of food products.Product modification. Significant ad-

vances have been made in the modifica-tion of food components, such as pro-teins, polysaccharides, fats, and oils.Protein modifications, for example, in-clude limited enzymatic hydrolysis toalter food functionality; the reverseprocess, the so-called plastein reaction,has been proposed as a method to createproteinlike materials to develop newfood products. Modification of proper-ties of proteins by combining informa-tion on crystal structure and proteinchemistry with artificial gene synthesis isalso being explored (3, 35).Meat tenderization with papain is one

example of the large-scale application ofenzymatic hydrolysis to modify productfunctionality. Other potential processesare the enzymatic reduction of limonoidbitterness in citrus products to improveflavor (36) and the modification of thefatty acid composition of triglycerides bylipases. One example is the enzymaticmodification of olive oil and stearic acid

to a fat similar to cocoa butter, particu-larly the formation of I-palmitoyl-2-oleyl-3-stearoly-rac-glycerol, the majortriglyceride of cocoa butter, which hasbeen obtained on reacting oleic anhy-dride with l-palmitoyl-3-stearoyl-rac-glycerol in the presence of lipase. Fur-thermore, the development of a two-stage microbial process for producingglycerides having cocoa butter charac-teristics requires mention (37).Product preservation. Historically,

there has been extensive use of microbialmetabolism for food preservation andstabilization, especially for dairy, meat,fish, fruit, and vegetable products (38).The efficiency of microorganisms used inthe food fermentation industries poten-tially can be enhanced by genetic ma-nipulation of starter cultures. However,additional fundamental knowledge of thegenetics, biochemistry, and molecularbiology of organisms used as starter cul-tures is required (39).Product safety, characterization, and

quality control. Besides the use of classi-cal methods to ensure the quality andsafety of food and to identify food com-ponents (40), three recent developmentsare relevant to product safety, character-ization, and quality control: (i) the poten-tial application of monoclonal antibodiesto determine optimal crop harvesting andproduct freshness (41), (ii) the use ofbiosensors and DNA hybridization tech-niques for quality control (42), and (iii)the potential of tissue culture and geneticmethods for nutrient and toxicity assess-ment (43). In addition, the regulatory andsafety aspects of biotechnology and theirimpact on the nutritional quality of theresulting food products are being exam-ined (44).Processing methods. Mechanical unit

operations used for product purificationand recovery include sedimentation,centrifugation, and filtration, along withdialysis, flotation, and ultrafiltration(45). Biomass separation is commonlyaided by bioflocculation or by the use ofsynthetic polyelectrolytes. Recently,natural polyelectrolytes such as chitinand chitosan have been investigated assubstitutes for synthetic polyelectrolytes(45, 46). Application of aqueous two-phase (liquid-liquid) systems for the ex-tractive purification of enzymes (47) andthe supercritical extraction (48) of foodingredients are becoming increasinglyimportant. In supercritical extraction,carbon dioxide is favored as the densegas because it is nontoxic, nonexplosive,cheap, readily available, and easily re-moved from extracted products (49).Supercritical extraction is currently used

SCIENCE, VOL. 229

on an industrial scale for decaffeinatingcoffee and tea. Scale-up of high-perform-ance liquid chromatography (HPLC)separation processes is also being ex-plored (50).

Nonlipolytic enzymes have been usedto enhance the extractability of oil fromseeds (51), and pectolytic enzymes areapplied to increase yields in the process-ing of liquid fruit and vegetable products(52). In addition, cofermentation pro-cesses have been suggested to aid theseparation and purification of secondarymetabolites (53).

Treatment and utilization of processwaste. Because of the large volumesinvolved in the production and process-ing of food, generated wastes create dis-posal and pollution problems. In addi-tion, there is a substantial loss of essen-tial nutrients. For example, 20 millionmetric tons of whey, the fluid that resultsfrom the separation of curd when con-verting milk into cheese, accumulate an-nually in the United States (54). Wheycontains more than half of the nutrientsof the milk used in cheese production,including 1 percent protein and 5 percentlactose. Approximately 50 percent of thetotal whey solids is disposed of in vari-ous industrial and municipal waste-treat-ment operations (55).Biomass recovery, especially isolation

of valuable protein by-products, hasbeen carried out in the food processingindustry for an extended period of time.The isolation of protein concentratesfrom potato processing wastes, for ex-ample, has been used on an industrialscale for several decades, and the prod-uct's potential for food application hasbeen investigated extensively (56). Dur-ing the past decade, ultrafiltration hasbecome useful in food processes, espe-cially for the recovery of whey proteinfrom cheese, cottage cheese, or industri-al casein processing wastes (57). By-product recovery has also been exploredfor application to the processing of meat,cereal, dairy, fruits and vegetables, andfish and shellfish, as well as fermentationoperations (58).The multifunctional potential of food

processing wastes for by-product recov-ery and conversion can be illustrated bythe case of chitin-poly-3 (1,4) N-acetyl-D-glucosamine-which is a waste prod-uct of the shellfish industry and one ofthe most abundant polysaccharides inthe world. It has been shown to havenumerous potential food applications,such as being used as a possible dietaryfiber, a functional ingredient, and animmobilizer of enzymes. Chitosan (par-tially deacetylated chitin) has been effec-20 SEPTEMBER 1985

tive in aiding the separation of colloidaland dispersed particles from food proc-ess wastes and has the potential for beingused for the microencapsulation offlavorand for the entrapment of whole cells(59). Chitin bioconversion to SCP hasalso been reported, and numerous addi-tional applications of chitin and chitosanare being investigated (60).

Bioconversion of food processingwastes includes the use of substratessuch as starch or whey. The so-calledSymba process utilizes a symbiotic cul-ture of two yeasts, Endomycopsis fibu-liger and Candida utilis, to convert pota-to starch into SCP. A Kluyveromycesfragilis and Candida intermedia symbi-otic culture, which is characterized by anexclusively oxidative lactose metabo-lism, is being used for production ofprotein-enriched whey (61). Other exam-ples of process waste bioconversions arethe application of molasses and cornsteep liquor as substrates in many fer-mentation processes and the productionof vinegar (from "waste" wine) (1). Fur-thermore, the anaerobic digestion offood wastes to provide methane for fueluse is now being used on a commercialscale (62).

Research Needs

As the above discussion indicates,there have been numerous achievementsin the field of food biotechnology andthere exist many more potential opportu-nities. One critical factor, however, isthe formulation of achievable objectivesto aid the rational improvement of foodproduction and processing technologiesand to reach desired goals for productquality. What is needed is a rationalprogram for the food sector that has astructure based on identification of es-sential research needs. Also needed isincreased investment in food researchand development, which currently con-stitutes only about 0.3 percent of indus-try-based business in the United States,as well as long-term commitments toresearch projects in food biotechnology.At a workshop sponsored by the Insti-

tute of Food Technologists, scientistsfrom industry, government, and acade-mia made the following statement con-cerning the research needs in this impor-tant area (63):

Biotechnology directed toward the generalarea of food can bring significant economicbenefits at both the macro and micro levels.The U.S. national (macroeconomic) interestscan be served by more reliable supplies ofcritical food and food ingredients; by the

development of methods of production whichdo not minimize the production capability ofthe growth environment; and by more effi-cient use of capital employed in food process-ing.

In addition, faster innovation, particularlyin agricultural raw material development, canoccur, thereby maintaining a competitive in-ternational position. Also, lower energy con-sumption in food processing can be expected,as well as the provision of an added valueusage for agricultural commodities currentlyin surplus.At the microeconomic level of individual

food sectors benefits will come from moreeffective production, improved ability to meetthe consumers' demands for natural foods andfood ingredients, less waste, improved proc-essing characteristics, consistent quality, anda greater nutritional value.

The following programs reflect re-search needs at the various steps in thepath that leads from agricultural produc-tion to the consumer:

1) Application of biotechnology to thestructural-functional relationship offoodmaterial. This program aims to improvethe utilization of biomaterials by apply-ing modern biotechnological principlesto control the functional performance offoodstuffs. In addition, biotechnologywill contribute analytical tools and proc-essing procedures that will aid in theimplementation of this new knowledge.

2) Cell physiology and biochemistryofagricultural raw materials. The poten-tial exists to lower the cost of agricultur-al raw materials, both plant and animal,by application of biotechnological tech-niques. Potential targets for improve-ment are (i) solids content, sensory prop-erties (color, flavor, texture), environ-mental adaptation, secondary metabo-lites (vitamins), and postharvest stor-ability in crops and (ii) feed efficiency,palatability, fat/protein ratios, fertility,and maturation time of juveniles in ani-mals.To realize these benefits, a vast in-

crease is necessary in our understanding(at the molecular level) of the cellularphysiology, including biosynthetic andregulatory pathways, of the appropriateanimal and plant species.

3) Improvement of enzymatic proc-essing. Enzyme processes can reducethe high cost of traditional food process-es and also permit development of totallynovel foods and food ingredients. Toexpand the range of possible processesand to improve on the economics ofcurrent enzyme-based processes, in-creased basic knowledge is needed onenzyme isolation and characterization,the mechanisms of enzyme action, andenzyme incorporation into food process-es. Specific needs are to understand themechanisms of enzyme inactivation; to

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utilize enzymes for biosynthetic process-es and redox reactions relevant to foods,including the low-cost production andrecycling of cofactors; and to developnew process procedures using immobi-lized whole cells. Fundamental studiesare needed on the control of mass trans-fer in food systems, maintenance of cata-lytic activity, and prevention of contami-nation. Also needed are computer mod-eling and understanding of the mecha-nisms of action of food processingenzymes in sufficient detail to permitsystematic protein engineering to im-prove enzymes.

4) Improvement offood-grade micro-organisms. Microorganisms-bacteria,yeasts, and fungi-are all used exten-sively in various aspects offood process-ing. To improve the economics (yieldand productivity) and new product char-acteristics achievable with these orga-nisms, major advances are needed in ourunderstanding of their biochemistry andgenetics. Specific research needs are (i)to establish recombinant DNA technolo-gies and a fundamental understanding ofmicroorganisms useful in food fermenta-tion and preservation processes; (ii) toquantitatively describe the microbialecology and biochemistry of mixed-cul-ture and solid-state fermentations impor-tant in foodstuffs; (iii) to isolate, select,and genetically manipulate organisms ca-pable of synthesizing food additives-such as biopolymers, colorants, naturalflavorings, and preservatives-by fer-mentation and cell culture; and (iv) todevelop economically viable biopro-cesses as sources ofraw materials for thefood processing industry.

5) Methods development. To improvethe production costs, nutritional value,and cost in use of some of the majoragricultural crops, particularly cereals,further fundamental advances in cell cul-ture methods and recombinant DNAtechnologies are necessary. Specific re-search needs are (i) vector developmentand transformation procedures for cerealcrops, (ii) improved regulation andexpression of foreign genes, and (iii)techniques to regenerate and propagatecrops that cannot now be so handled. Toreduce the time and cost of developingnew crop species, rapid screening meth-ods are required to identify the desiredgenotype at the cell culture stage.

6) Food safety. There is an urgentneed to improve and to accelerate tech-niques of food safety assessment. Bio-technology can contribute to food safetyby increasing the sensitivity and specific-ity of such assays and by developingfaster and more meaningful methodolo-

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gies based on DNA hybridization, se-quencing, and monoclonal antibodytechniques.The most critical research needs, in

addition to basic studies on the struc-ture-function relationship offood materi-als, are fundamental studies in the cellphysiology and biochemistry of agricul-tural raw materials and improvement offood-grade microorganisms.

Conclusions

Biotechnology applied to food produc-tion and processing clearly encompassesa very large and diverse field. The utili-zation of the capabilities of biologicalsystems is rapidly expanding into a vari-ety offood applications, and consequent-ly many new food sources, processes,and products are being developed. Inaddition, the identification of critical re-search needs will help to enhance foodproduction and processing.We have attempted to highlight bio-

technology in food production and proc-essing in broad terms, and consequentlywe recognize that we have only touchedon many of the exciting involvements ofbiotechnology in providing, securing,and improving the world's food supply.

References and Notes1. H. J. Rehm and P. Pr&ve, in Handbuch der

Biotechnologie, P. Pr&ve, U. Faust, W. Sittig,D. A. Sukatsch, Eds. (Oldenburg Verlag, Mu-nich, West Germany, ed. 2, 1984), p. 1; A. L.Demain and N. A. Solomon, Sci. Am. 245, 67(September 1981); H. J. Rehm and G. Reed,Biotechnology, vol. 5, Food and Feed Produc-tion with Microorganisms (Verlag Chemie,Weinheim, West Germany, 1983); A. H. Rose,Industrial Microbiology (Butterworths, Wash-ington, D.C., 1%1); H. J. Rehm, IndustrielleMikrobiologie (Springer Verlag, Berlin, 1967);D. Knorr, Ed., Impact of Biotechnology onFood Production and Processing (Dekker, NewYork, in press).

2. P. Dunnill and M. Rudd, Biotechnology & Brit-ish Industry (Science and Engineering ResearchCouncil, London, 1984), p. 23; B. J. Liska andW. W. Marion, Food Technol. 39(6), 3R (1985).

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64. We thank the participants of the biotechnologytopic at the IFT workshop on research needs,especially A. J. Stevens. Valuable comments ondrafts of this article were provided by S. P.Shoemaker, M. J. Haas, K. Venkat, P. M.Walsh, and D. Kukich.

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