1

QUALITY EVALUATION AND CONTROL

3202Luke Howard

ProfessorFood Science Department

University of Arkansas

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INTRODUCTION

• This module represents a brief overview of the course FDSC 4203; Quality Evaluation and Control taught by Dr Luke Howard at the University of Arkansas.

• It is narrated by Dr Steve Seideman, Extension Food Processing Specialist of the Institute of Food Science & Engineering, University of Arkansas.

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INTRODUCTION

• The module will cover quality assurance, plant sanitation, GMPs, cleaning and disinfection methods, quality factors and standards, flavor and color determination, food additives and HACCP

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Quality Assurancein the Food Industry

(Portions of this section are from the book entitled “ Total Quality Assurance for the Food Industries” by Dr Wilbur Gould and Ronald Gould. CTI Publications,Inc)

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Quality Assurance• Modern term used for describing the

control, evaluation and audit of a food processing system

• It’s primary function is to provide confidence for management and the ultimate customer (consumer)

• The customer establishes the level of quality the firm must manufacture

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Canning & Quality Assurance

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Quality Control

• A large part of a QA program is built around quality control

• Quality control means to regulate to some standard

• It is an important tool for the production worker to help operate the line in conformance with the predetermined parameters for any given quality level

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Quality Evaluation

• Is also part of a QA operation

• It is used to describe or appraise the worth of a product

• It generally involves taking a measurement of the product in a laboratory

• It includes the evaluation of all incoming materials, products in process, and/or finished products

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Quality Audit or Verification

• Goal is to audit or verify the products or processes over time

• Used for firms having many plants

• Part of the QA program to verify products in the warehouse, in distribution, and/or competitors products in the market place

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Quality

• Makes a product what it is, varies among consumers

• “Is the combination of attributes or characteristics of a product that have significance in determining the degree of acceptability of the product to a user”

• Repeat sales are related to QA practices

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Standards for Quality

• Legal standards

• Company or voluntary label standards

• Industry standards

• Consumer or grade standards

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Subjective Methods for Determining Quality

• Based on the opinion of the investigators

• Usually involves sensory perception i.e. flavor, color, odor, touch, freedom from defects etc.

• Requires training and experience

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Objective Methods for Determining Quality

• Physical - size, texture, color, consistency, imperfections, headspace, drained weight, vacuum

• Chemical - enzyme conc., moisture, fiber, pH, acidity

• Microscopic - used for adulteration and contamination, and differentiation between cell types, tissue types and microorganisms

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QA Program Functions (1)

• Raw materials specifications for QC

• Improvement of product quality

• Improvement of processing methods with resulting savings in cost of production and > profits

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QA Program Functions (2)

• Standardization of the finished product according to label specifications

• Increased order and better housekeeping of a sanitary plant

• Greater consumer confidence (uniform high quality)

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Basic Fundamentals for a Successful QA Program

• Organization of the QA department• The personnel• Sampling• Standards and specifications• Measurement

A. laboratory C. procedures

B. equipment D. reports• Interpretation (SQC and SPC)

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Examples of QE Functions (1)

• Determination of % germination and purity of seed

• Soil and tissue analysis

• Collection and summarization of weather data for use in scheduling of raw products, packaging materials, or labor

• Identification of crop diseases and insects

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Examples of QE Functions (2)

• Determination of raw product quality and other in-coming raw materials

• Evaluation and continuous monitoring of processing variables affecting quality

• Determination of the efficiency of each processing operation as related to finished product quality

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Examples of QE Functions (3)

• Periodic and continuous monitoring of water supply, equipment, plant sanitation, and the waste disposal system

• Evaluation of the finished product quality and assurance of the storage life of the finished product

• Development of new products and improvement of present processing, production and quality evaluation methods

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Basic Equipment for QE

• Can opener• Vacuum gauge• Headspace gauge• Grading scale, screens and trays• Sizing gauges• Brine and syrup cylinders• Hydrometers and salometers• Thermometers

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Specialized Equipment for QE

• Colorimeter

• pH meter

• Refractometer

• Viscometer

• Moisture analyzer

• Microscope

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Factors Affecting Quality

• Cultivar

• Maturity

• Cultural practices

• Harvesting and handling

• Processing

• Shelf-life

• Use

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Food Plant Sanitation

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Plant Sanitation Industries Responsibility

• Moral and legal obligation to perform all operations in clean surroundings, and with due regard to the basic principles of sanitation

• FDC Section 402a4 states that a food shall be deemed to be adulterated “if it has become contaminated with filth, or whereby it may have been rendered injurious to health”

• Sanitation is every person’s job in the plant

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Reasons for Plant Sanitation

• A better product, competition demands high, consistent quality

• A more efficient operation, efficiency equates to planned sanitation

• Greater employee productivity

• Improved safety

• Is a barometer of overall plant conditions

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Plantkeeping - Exterior

• Grounds maintained• Storage for

equipment.• Exterior openings

screened• Free from insects,

rodent proof• No uncovered

openings• No chemical spills

• Remove broken containers from shipping, receiving

• No trash in parking lot• Paved roads• No litter or waste

accumulation• Roofs leak proof

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Plantkeeping - Building

• Floors water tight, smooth surfaced, and sloped 1/8” to 1/4” per foot to floor drains every 10’ apart

• Drains covered with grates

• Walls doors, partitions, pipes, ceilings kept cleaned and painted

• Proper ventilation to prevent condensation, mold growth, or deterioration of structures

• All windows, doors and openings should be screened

• Good lighting, ranges from 25 to 150 foot candles

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Plantkeeping - Equipment

• Constructed in regard to cleanability and protection from contamination

• Materials should be smooth, hard, non-porous, preferably stainless steel

• Pipe lines, fittings handling food should be sanitary

• Eliminate sharp corners

• Equipment should be directly accessible for cleaning (CIP)

• All open equipment should be covered

• Containers should be clean, and not used for other purposes (tight lids)

• Waste should be collected in proper containers (removed daily)

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Plantkeeping - Storage

• Aisles should be kept clean and well marked

• Food materials, packaging should be protected from damage, rodents, insects, dirt, dust

• Stored products should be stored away from walls at proper storage temperatures

• Storage areas cleaned weekly

• Inventory and evaluation of warehouse products should be conducted frequently

• Storage temperature is critical for perishable ingredients/products

• Policy of FIFO should be strictly adhered to

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Plantkeeping - Employees

• Must wear caps, hair nets, hair restraints

• Pins, curlers, jewelry, fingernail polish should not be worn

• Pens, pencils, watches should not be worn above the waistline

• Protective clothing worn at all times

• Gum chewing and tobacco use restricted to confined areas

• Glass bottles not permitted in working areas

• Employees must report any skin breaks to supervisors

• Observe proper habits of cleanliness

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Plantkeeping - Employees

• Hands shall be washed and sanitized at the following times:

A. When reporting to

work

B. After breaks

C. After smoking or

eating

D. After picking up

objects from the floor

E. After blowing nose

F. After coughing,

sneezing and covering

mouth with hand

G. After using the toilet• Signs should be posted

throughout the facility as to smoking, eating and washing habits, and general sanitary requirements

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Plantkeeping - Special Areas

• Special storage areas should be provided for handling of clean uniforms, towels, toilet articles, soiled uniforms and linens, custodians supplies and equipment, pesticides, employees belongings, and garbage and wastes

• Restroom facilities should include liquid soap, drying towels

• Restrooms should not open to processing areas

• Toilet facilities should be scrupulously clean

• Lunchroom facilities should be provided and kept clean

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Plantkeeping - Materials

• In-coming materials should be carefully inspected and inventoried

• Outgoing materials should be properly identified in terms of shipments and quality

• Great losses occur in warehouses by improper housekeeping practices i.e. breakage, pilferage, looting etc.

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Plantkeeping - Sanitary Organization

• The authority to uphold standards of sanitation is the responsibility of the plant sanitarian (in small plants might be the QA director or plant supervisor)

• Sanitarian should be well trained in microbiology, chemistry, entomology, parasitology, and sanitary engineering

• Sanitarian should be directly responsible to management

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Plantkeeping - Sanitary Organization

Required tools for sanitarians• Ample supply of potable water• Different types of brushes• Detergents and knowledge of their use• Chlorination and chlorinating equipment• Steam and/or high pressure equipment fitted

with proper nozzles

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Plantkeeping - Sanitary Organization

• Flashlights for inspection of out of way places

• Black light for detection of rodents• Camera• Attire consisting of white cap, clean white

overalls, or white shirt and pants• Is responsible for training courses,

workshops, seminars on sanitation and GMPs

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Plant Inspection

• Plant inspection may be conducted by company personnel from either the home office, or the local plant, or by a third party

• A written report should be made in all observed conditions listed as satisfactory, needs improvement or unsatisfactory

• A manual should be written documenting minimum standards for each of the plant areas

• Report should be acted on accordingly

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Sanitation Evaluation

• Physical cleanliness - absence of visual product waste, foreign matter, slime etc.

• Chemical cleanliness - freedom from undesirable chemicals i.e. cleaning compounds, germicides, pesticides, which might be present on the product or equipment

• Microbiological cleanliness - controlled by the amount of microorganisms that may be present in the product, or on the equipment, building or people

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Suppliers

• Chemical supplier can assist in plant audit for developing a sanitation program

• Supplier can outline specific cleaning methods, products, and exact amounts, times and temp’s

• Labor amounts to 90% of a cleaning program• Supplier can provide control and feeding

equipment, engineering services, technical assistance, laboratory services, and sound planning for future needs

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Sanitation Program• Plant sanitation committee should meet

monthly• Sanitation committee may consist of: plant

manager, production supervisor, QA supervisor, food technologist, maintenance engineer, personnel supervisor and sanitarian

• Training and retraining is critical• Break down each job into components to

instruct, try to get people to think about what they are doing, stress important repetitive situations

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Cleaning and Disinfection Methods

Portions of this section were taken from an article entitles : Sanitation; The Key to Food Safety and Public Health by James H. Giese. Food Technology. December 1991.

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Challenges for Food Sanitation

• Increasing number of older consumers (immuno-compromised individuals)

• New products and processes (eg’s MAP, sous vide, aseptically packaged foods

high pressure, pulsed electric fields)

• Sanitation programs are a prerequisite for HACCP programs

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Plant Design

• Layout and functioning of the processing line should facilitate the flow of food material from one operation to the next with a minimum of delay

• Walls, floors and ceilings should be made of impervious, easily cleaned, non-painted inert material

• Positive air pressure should be maintained

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Plant Design

• Raw materials should be isolated from processed food

• Adequate hand-washing stations should be provided in food processing areas

• Horizontal structures such as pipe hangers, beams, and duct work over exposed product areas should be eliminated

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Plant Design

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Plant Design

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Sanitation: A Four Step Process

• A pre-rinse with high pressure water to remove gross soil

• Physical removal of soil by detergents and mechanical aids

• Another rinse to remove the detergent and loose soil

• The application of sanitizers to prevent recontamination before processing

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Water Functions and Quality

• Carrier for detergents and sanitizers• Carries soils or contaminants away from the

surface that has been cleaned and sanitized• Water hardness is responsible for excessive

soap and detergent consumption, mineral deposits, undesirable films, and precipitates

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Rinsing Step

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Efficacy of Detergents

• Should wet and penetrate soil• Should emulsify fat• Should disperse and suspend soil• Should counteract water hardness• Should rinse well to prevent soil

from redepositing on clean surfaces and be non-corrosive to equipment

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Alkaline Detergents

• Compounds used for removal of organic soils, such as oils, grease, proteins and carbohydrates

• Strongly alkaline compounds (pH > 13) eg’s NaOH

• Moderately alkaline compounds (pH 10-12) eg’s sodium metasilicate

• Mildly alkaline compounds (pH 7-12) eg’s sodium carbonate and sodium sesquicarbonate

• Complex phosphates eg’s TPP, SHMP

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Acid Detergents

• Compounds for removal of encrusted soils and deposits formed from application of alkaline detergents

• Strong inorganic acids eg’s hydrofluride, hydrochloride (scale removal in boilers, are corrosive to stainless steel)

• Organic acids eg’s citric and hydroxyacetic acids (used in manual cleaning formulations, also function as water softeners)

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Detergent Auxiliaries

• Incorporated with cleaning compounds to improve their performance, provide filler material or bulk, condition water and protect sensitive surfaces

• Surfactants are organic compounds used in both alkaline and acidic formulations to increase soil penetration, improve rinsing, or to control foaming

• Sequestrants combine with magnesuim and calcium salts eg’s SPP, EDTA, sodium gluconate

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Sanitizers

• Soil should be completely removed prior to sanitizing “You can’t sanitize a dirty surface”

• Efficacy is affected by; time, pH, temperature, concentration, water hardness and surface cleanliness

• Chambers test requires that sanitizers produce a 99.999% kill of 75-125 million E. coli and Staphylococcus aureus within 30 sec. After application at 20oC

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Regulation of Sanitizers and Cleaners

• FDA approves components of sanitizers by their chemical names, and determines a maximum use concentration on product contact surfaces

• EPA requires specific label information regarding usage and application requirements

• USDA authorizes cleaning and sanitizing compounds for use in federally inspected meat poultry, and egg processing plants

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Important Properties of Sanitizers

• Ability to provide a rapid antimicrobial activity against a range of organisms

• Be readily available, inexpensive and ready to use

• Have stability and resistance to the presence of organic matter, detergent and soap residues

• Ability to work in a wide range of pH, water hardness, and temperatures

• Lack of toxicity to humans, and non-corrosive, and water soluble

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Halogens

• Chlorine compounds - most popular and commonly used sanitizers

• Hypochlorous acid (HOCL) is the active killing agent, is strongly affected by pH (opt. 6.5-7.5)

• Kills bacteria by reacting with and disrupting cell walls

• Sodium hypochlorite is the most common form, but calcium hypochlorite, and Cl- gas are also used

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Chlorine Reaction in Water

Cl2 + H2O HOCL + H+ + Cl-

NaOCL + H2O HOCL + Na+ + OH-

NH2CL + H2O HOCL + NH2 + OH-

HOCL H+ + OCL-

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Chlorine Dioxide

• Widely used in water and sewage treatment, becoming more popular with food processors

• Has 2.5 times the oxidizing power of chlorine• Can be used at much lower concentrations• Less sensitive to pH• Must be generated on-site

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Iodine Compounds

• Free elemental iodine and hypoiodous acid are frequently used antimicrobial compounds

• Alcohol-iodine solutions and iodophors are also commonly used

• Iodophors are aqueous solutions of a nonionic surfactant and complexed elemental iodine

• Iodophors are used for sanitizing utensils, equipment and as skin antiseptics

• Narrow pH range (2.5-3.5)

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Quaternary Ammonium Compounds

• “Quats” are cationic surfactants used on floors, walls, and aluminum equipment

• An excellent application is on equipment in storage or when contact time will exceed 24hr

• Effective over a wide pH range (6-10), and at high temperatures, noncorrosive to metals, and unaffected by high levels of organic matter

• Effective against molds and gram negative slime formers

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Acid-Anionic Sanitizers

• Commonly used in automated cleaning systems, which combine sanitizing with a final rinse

• Phosphoric acid is the most common form, with maximum antimicrobial activity below pH 3

• Particularly suited for stainless steel, they can be used to help prevent mineral deposits by neutralizing excessive alkalinity

• They have rapid activity against most microorganisms, a low corrosive effect, resistance to organic matter and hard water salts

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Hot Water and Steam

• Antimicrobial activity depends on the temperature, humidity and exposure time

• Hot water is convenient and cost effective, and is commonly used for sanitizing food contact surfaces, small equipment parts, utensils, and heat exchangers

• Steam is sometimes used to sanitize conveyor belts or other equipment in-place

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Equipment and SystemsManual Aids

• Brushes should have a block constructed of durable material resistant to heat, chemicals and moisture

• Bristles should be nylon, with good water holding capacity to carry cleaning solution to contact surfaces

• Scrapers and scouring pads should be used to remove baked-on deposits and encrusted soil from equipment and other surfaces

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High Pressure Systems

• Utilize high pressure hot water to remove soil• Provides a very effective cutting action to

remove gross soil build-up from equipment• It is best utilized to clean hard-to-reach areas,

conveyor systems, and outside surfaces of equipment, walls and floors

• Provide a good way to reduce manual labor costs

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Foam Cleaning Systems

• These systems mix a metered amount of air and detergent solution to form a clinging foam

• Can be applied to areas that are inaccessible for hand cleaning

• Major difference between high pressure and foam cleaning are the application of foam at a lower PSI and its longer contact time

• Longer contact time allows soil to loosen and then removed

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Foam Cleaning System

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Clean-Out-of-Place (COP)

• Requires disassembly of equipment after rinsing so that parts and short pipe sections may be placed in a recirculation tank for cleaning by physical and chemical action

• Normal length of time for wash solution recirculation is ca. 30-40 min with an additional 5-10 min for a cold acid or sanitizing rinse

• Typically used for filling machine parts, centrifuge parts, pump heads and parts, pipe sections, take down fittings, homogenizer parts

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Clean-In-Place (CIP) Systems

• Becoming popular due to labor savings and automated control (milk plants, aseptic systems)

• One shot systems have one tank for circulating the wash water and then discharging at the end of the rinse cycle

• Two tank systems consist of one tank for rinse water and another tank for reclaiming the cleaning solution, while three tank systems contain one tank for cleaning solution, one for reclaiming pre-rinse solution, and one for a final water rinse

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Clean-In-Place System

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Sanitizer Application Equipment

• Portable pressure sprayers

• Centralized systems can provide consistent sanitizer concentration and convenient hookups

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Factors Affecting Sanitizer Efficacy

• Initial microbial load on raw product

• Water quality, chemistry and temperature

• Biofilm formation

• Concentration, temperature and contact time of sanitizer

• Organic matter content on the product and in the water

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Quality Factors and Standards

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Appearance FactorsSize and Shape

• Can be easily evaluated and are important factors in federal and state grade standards

• Performed manually or by automated separating and grading equipment

• Eggs pass through different sized openings, and rollers, separation by weight after manual grading

• Curvature of cucumbers for pickling

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Size and Color Sorting

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Sorting

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Weigh Grading

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Color Sorting

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Color Sorting

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Appearance FactorsColor and Gloss

• Indicates degree of ripeness of fruits/vegetables• Quality of fried potatoes• Bleaching of dried tomato powders• Surface color of chocolate indicates storage

history• Color of a food foam or batter varies with the

density and can indicate a change in mixing efficiency

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Food Color

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Color Measurement

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Appearance FactorsColor Measurement

• Color of transparent liquids such as beer, wine, grape juice are measured using spectrophotometers and colorimeters

• Color of liquid or solid foods are measured by comparing the reflected color to defined colored tiles or chips

• Color of many foods is measured using colorimeters, define the hue, chroma, and brightness of reflected light from food surfaces

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Colorimeters

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Hunter Color Solid

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Color Wheel

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Appearance FactorsGloss Measurement

• Light measuring instruments are available that measure the shine, or gloss of a food surface

• Gloss is important to the attractiveness of gelatin deserts and buttered vegetables

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Gloss Meter

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Appearance FactorsConsistency

• Textural as well as appearance factor• Consistency of foods is measured bt their

viscosity, higher viscosity products being of higher consistency and lower viscosity being lower consistency

• Measuring devices include, consistometers (Bostwick), and viscometers (Brookfield, Cannon-Finske)

• Used for ketchup, honey, syrups, puree’s

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Viscometers

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Viscometers On-Line

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Viscometers

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Rheological Properties

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On-Line NIR for Chemical Analysis

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Textural Factors

• Texture refers to those qualities of food that we can feel either with the fingers, the tongue, the palate, or the teeth

• Texture is an important quality attribute for many foods including; chewing gum, crackers, chips, fruits, bread products, meats etc.

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Measuring Texture

• Measurements of resistance to force

• Many different types of instruments are available to measure different types of force (e.g.succulometers, penetrometers, consistometers, tenderometers).

• Force-distance curves give important information about the rheological properties of foods

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Texture Changes in Foods

• Water content plays a major role (e.g. firmness of fruits and vegetables, bread staling, freezer burn etc ).

• Food composition is also important

• Lipid, starch, protein, and sugar content affects functional properties of foods

• Many food ingredients may affect textural properties

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Texture Analyzers

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Texture Analyzers

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Texture Profile Analysis

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Texture Profile Analysis

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Flavor Factors

• Flavor is a combination of taste and smell, is largely subjective and thus, difficult to measure

• Flavor is affected by the basic taste attributes (sweet, sour, bitter, salty), and numerous volatile compounds which affect aroma

• Flavor is measured using analytical instrumentation and sensory tests

• A goal of many QC groups is to identify chemical measurements that may be used to predict sensory quality

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Odor Determination

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Electronic Nose for QC

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Sensory Panels

• Consumer preference groups - untrained panels that can provide a good insight into what consumers generally will prefer

• Trained panels - are selected on the basis of their flavor sensitivity and trained to recognize attributes and defects of a particular product

• Triangle and preference tests are commonly used for QC functions

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Sensory Analysis

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Additional Quality Factors

• Nutritional quality - assessed by chemical or instrumental analyses

• Sanitary quality - measured by counts of bacteria, mold, yeast, insect fragments, also rocks, stones, glass fragments, metals are identified using x-ray machines and metal detectors

• Keeping quality - shelf life studies, ASLT

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Quality Standards

• Research - internal standards set up by a company to help ensure the excellence of its products

• Trade - standards set up by members of industry on a voluntary basis to assure at least minimum acceptable quality

• Federal grade standards - have been set up mainly to help producers, dealers, wholesalers, retailers and consumers in marketing food products, provide a common language for trading

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Federal Grade Standards

• Standards of quality administered by the USDA Marketing Service and the FSIS

• Grading - is voluntary and is used to determine the quality of products such as meats

• Inspection - is mandatory and assures the wholesomeness of products

• Uniform grades of quality established for > 100 foods (meat, dairy, poultry, fruits, vegetables, seafood)

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Federal Grade StandardsMeats

• Age of the animal• Amount and distribution of muscle fat (marbling)• Firmness and texture of the flesh• Color of the lean meat• Federal grade marks for beef are; Prime,

Choice, Select, Standard, Commercial, Utility, Cutter, Canner

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USDA Standards of Composition and Identity

• Minimum content requirements for federally inspected meat and poultry products (canned or frozen)

• For example, the USDA minimum requirement for beef stew specifies the minimum percentage of beef only (25%), that the stew must contain

• Complete standards of identity have been established for chopped ham, corned beef hash, and oleomargarine

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FDA Standards of Identity

• Establishes what a given food product is

• Example - what a food must contain to be labeled preserves

• Includes both mandatory ingredients and optional ingredients

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Minimum Standards of Quality

• Have been established for many canned fruits and vegetables to supplement standards of identity

• Examples include; tenderness, color and freedom from defects

• If a food does not meet the FDA quality standards it must be labeled “below standard in quality”

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Flavor Determination

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Food Flavor• Involves at least two phenomena, taste and odor• When we say a food tastes good, we actually

mean it has a good taste and aroma• Taste: is the subjective experience (sensation)

resulting from stimulation of the chemosensory receptors (taste buds) located on the oral cavity by chemicals or chemical components of food in solution with saliva

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Basic Taste Attributes

• Salty

• Sweet

• Sour

• Bitter

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Taste

• Strictly tongue taste, not flavor

• Taste originates from compounds in solution (saliva)

• All taste buds can detect all four qualities, but some respond to one quality better than the other three

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Salty Quality

• Is the result of ionic stimulation• Na+ is responsible for eliciting salty taste,

while anions especially Cl- are inhibitory• Many inorganic salts in solution taste

differently depending on molecular concentration eg. at low concentration many salts taste sweet, with increasing concentration the taste may be salty, sour or bitter

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Sour Quality

• Chemical stimulus is the hydrogen (H+) ion

• The threshold number of hydrogen ions necessary for perception of a sour taste is smaller for weak acids than for strong acids

• Indicates that the anion or undissociated acid may modify the taste of these compounds

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Sweet Quality

• Is elicited by a variety of food related organic compounds

• Most common sweetners are sugars, which vary considerably in sweetness

• Based upon equimolar solutions

fructose > sucrose > maltose > glucose > lactose

• Sweetness is affected by concentration, food medium, and temperature of food medium

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Bitter Quality

• Is difficult to associate with a specific stimulus

• Most prominent class of bitter tasting compounds are the alkaloids (caffeine, quinine and nicotine)

• Other include heavy halide salts, amino acids and phenolics

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Typical Thresholds for Taste Attributes

• Sweet (sucrose) 0.250% - 2500 ppm

• Bitter (caffeine) 0.016% - 160 ppm

• Sour (citric acid) 0.200% - 2000 ppm

• Salty (NaCl) 1.500% - 15,000 ppm

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Food Smell or Odor

• Refers to sensations resulting from stimulation of the chemosensory receptors located in the olfactory epithelium of the nose by airborne chemical compounds

• Chemicals may reach the epithelium directly through the nares, or indirectly (rostronasally), through food present in the mouth

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Food Smell or Aroma

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Color Determination

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Color

• Consumers typically select a food based upon it appearance and color

• Color can be measured more easily than taste, odor or texture

• Color is one portion of the input signals to the human brain that results in the perception of appearance

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Color

• Color as seen by the human eye is an interpretation by the brain of the character of light coming from an object

• We need to define color in a physical sense as objectively as possible and interpret the output in terms of how the human eye sees color

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Color

• Defined as: the aspect of radiant energy of which a human observer is aware through the visual sensations which arise from the stimulation of the retina of the eye

• Color is a characteristic of light, that is measurable in terms of intensity and wavelength

• It arises from the presence of light in greater intensities at some wavelengths than at others

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Fates of Light When Illuminated

• Reflected

• Transmitted

• Absorbed

• Refracted

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Color Perception

• If all light is reflected from an opaque surface, the object appears white

• Is some light is absorbed, the object appears gray

• If all light is absorbed, the object appears black

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Color Perception

• The perception of color results from differences in absorption of radiant energy at various wavelengths

• Maximum reflection in the short wavelength range (400-500 nm) results in blue

• Maximum reflection in the medium wavelength range (500-600 nm) results in green or yellow

• Maximum reflection in the long wavelength range (600-700 nm) results in red

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Colors in the Visible Spectrum

450480

520575 590

680

0

100

200

300

400

500

600

700

Wav

elen

gth

(nm

)

PurpleBlueGreenYellowOrangeRed

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Physiological Basis of Color

• The human eye has two types of sensitive cells in the retina

A. Rods - are sensitive to lightness & darkness

B. Cones - are sensitive to color

a. one set is sensitive to red light

b. one set is sensitive to green light

c. one set is sensitive to blue light

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Physiological Basis of Color

• Cones send a signal to the brain that sets up a response in terms of opposing pairs

A. One pair is red-green

B. One pair is yellow-blue

• This is why some individuals are red-green, or blue-yellow color blind

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Color MeasurementMunsell System

• Contains 1225 color chips used for convenient visual comparison

• Each chip has a numerical designation• Advantages: simple, convenient, easy to

understand• Examples: color grades for tomato juice, glass

color standards for sugar products, plastic color standards for peas, lima beans, apple butter, peanut butter, canned peaches, mushrooms

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Color MeasurementMunsell System

Disadvantages• Plastic and glass standards are available in a

limited number of colors• Painted paper chips come in an array of colors,

but are fragile, and fade with time• Repeated visual judgements are tiring and

tedious• Color that fall between existing standards are

difficult to communicate to other individuals

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Spectrophotometric Measurement of Color

• Early instrumental methods for color measurement were based on transmission, or reflection spectroscopy

• Researchers developed the response of the cones in the eye in terms of the visible spectrum

• X (red), Y (green) and Z (blue) were used as reference stimuli

139

Spectrophotometric Measurement of Color

• If we take the red, green, and blue data for the spectral colors, transform them to X, Y, and Z coordinates, and plot the response of the human cones against wavelength, we get the response of the human eye to color

• These curves were standardized in 1932 and called the CIE (International Commission of Illumination) x, y, z standard observer curves

140

Spectrophotometric Measurement of Color

• Having the data in the standard observer curves, it is mathematically simple to calculate color from a reflectance or transmission spectrum

• The sample spectrum is multiplied by the spectrum of light source and the area under the resultant curve is integrated in terms of the x, y, z curves

• The resulting figures for X,Y, Z specify the color of the sample

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Food Additives

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History of Food Additives• Smoking and sun drying were early

methods used for food preservation

• Much of our history is an indirect result of man’s quest for spices and other flavorings eg’s Marco Polo’s travels, discovery of America by Columbus, Cortez and the vanilla bean

• Texas settlers in the 1800’s - chili powder

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Food Additives

“ A substance or mixture of substances, other than a basic foodstuff, which is present in a food as a result of any aspect of production, processing, storage or packaging”

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Food Additive Categories

• Intentional additives - Those which are added to perform a specific function. They are measured and added in scientifically controlled amounts; therefore the amounts added are generally small.

• Incidental additives - Substances present in foods in trace quantities as a result of some phase of production, processing, storage or packaging. These are unavoidable from a practical viewpoint.

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Reasons for Using Food Additives

• Rapidly expanding population, and migration of the population from rural to urban areas

• With < 5% of the population growing food for the remaining 95%, much of the food would never reach consumers in edible condition without additives

• Additives help the food supply to be palatable, convenient, nutritious, safe, with a long shelf-life and pleasing flavor

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Food Preservative Categories

1). Those which act to control or prevent growth of microbes

• Salts or various acids such as proprionic, sorbic and benzoic

• Calcium proprionate - mold inhibitor in bread• Potassium sorbate - mold inhibitor in cheeses,

syrups, jams, mayonnaise and pickles • Sodium benzoate - mold inhibitor in high acid

foods, fruit drinks, carbonated beverages

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Food Preservative Categories

• Nitrates - prevent the growth of Clostridium botulinum in cured meats, also fixes the color and enhances the flavor of these products

• It is possible that nitrites combine with amines in the stomach to form nitrosamines

• These compounds are under investigation as possible carcinogens

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Food Preservative Categories

2) Preservatives which act by inhibiting detrimental chemical changes

• Prevention of rancidity in fatty foods can be accomplished with BHA, BHT, propyl gallate

• Citric acid, phosphoric acid and ascorbic acid are often added to enhance the effectiveness of BHA and BHT

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Food Preservative Categories

• Chelating or sequestering agents (EDTA and SHMP) are added to foods to bind trace metals which can act as catalysts in food spoilage

• These agents are used to prevent or reduce discoloration, clouding and rancidity

• Used in products such as soft drinks, cream style corn, shrimp and beer

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Flavoring Agents

• Sugar and salt are the most widely used additives

• Sugar not only contributes sweetness, but it also adds body to beverages, tenderness to baked goods, and color when caramelized

• Salt and sugar also may be used as preservatives at high concentrations

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Flavoring Agents

• Non-nutritive sweetners such as saccharin and aspartame are commonly used

• MSG, combines with protein to enhance the flavor of high protein foods, but does not contribute a flavor of its own.

• Disodium inositate and disodium guanylate are also used as flavor enhancers in dry soup mixes

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Coloring Agents

• Natural coloring agents include; annatto, carotenes, cochineal

• Annatto - commonly used in dairy products, margarine, cheese and ice cream

• Cochineal - added to meat products, spices and baked goods

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Coloring Agents

• Synthetic agents include; FD&C yellow #5 and red #4

• The soft drink industry is one of the prime color users

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Stabilizers and Thickeners

• These compounds may be derived from natural plant extracts, chemically modified natural products, or may be completely synthetic products

• Stabilizers are added to chocolate milk to prevent chocolate particles from settling out, or added to ice cream to bind excess water, this preventing ice crystals and a grainy texture

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Stabilizers and Thickeners

• Thickeners are added to icing, cheese spreads, salad dressings, pie fillings, soups and gravies to provide the desired consistency

• Additives such as sodium alginate, cellulose gums and pectins are used to provide body to sugar-sweetened soft drinks

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Emulsifiers and Surface Active Agents

• Emulsifiers permit the dispersion of tiny particles or globules of one liquid in another

• An oil and vinegar salad dressing illustrates one important use of emulsifiers

• Emulsifiers such as mono-glycerides play an important role in the baking industry by helping to increase volume, uniformity, fineness of grain and shelf life

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Emulsifiers and Surface Active Agents

• Lecithin, one of the most widely used emulsifiers, is a natural substance found in both plant and animal tissues

• Surface active agents (surfactants) of which emulsifiers are one type are used to lubricate foods (reduce slipperiness)

• Applications include; prevention of stickiness in peanut butter and caramel products

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Nutrition Supplements

• Fruit acids (citric, malic, acetic, tartaric) are used to intensify flavors in many food products including sherbets, cheese, grape and lime beverages, jams, jellies, candies and pickles

• Ammonium bicarbonate, sodium carbonate and calcium carbonate are examples of alkalies which are used to prevent a food product from becoming too acid

• Compounds are used to reduce the acidity of wines, control acidity of in canned peas and olives

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Firming Agents

• Firming agents improve the texture of processed fruits and vegetables

• Calcium chloride, calcium lactate and aluminum sulfate (alum) are used to improve the texture of pickles, maraschino cherries, and canned peas, tomatoes, potatoes and apples

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Anticaking Agents

• Anticaking agents are important in the salt industry where sodium silico aluminate is used to prevent particle clumping

• Calcium phosphate performs the same function in “Tang”type drinks

• Corn starch is added to powdered sugar to keep it free-flowing

• Calcium stearate in garlic salt is another example of the use of anticaking agents

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Leavening Agents

• A leavening agent is any chemical or biological substance that can produce bubbles of gas in dough

• These gas bubbles expand, causing the dough to rise; thus yielding foods which are light in texture

• Yeast was originally used, but is not a reliable source of gas

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Leavening Agents

• Baking powders have replaced yeast as the preferred leavening agents

• These powders are generally composed of sodium bicarbonate, an acid salt such as calcium monophosphate, and starch

• The phosphate and bicarbonate readily react in the presence of water to produce carbon dioxide

• The starch helps keep these ingredients dry and non-reactive, so that a given volume of baking powder will create a given amount of gas

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Maturing and Bleaching Agents

• The bleaching process of milled flour is accelerated by the addition of certain chemicals such as chlorine or chlorine dioxide in the form of a gas

• These compounds make it possible to produce consistently high quality flour, and avoid the problems created by prolonged storage, with little loss of nutritive quality

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Humectants

• These are substances such as propylene glycol, sorbitol, glycerine and mannitol which are added to foods to help keep them moist

• Proplyene glycol is added to shredded coconut and marshmallows, dried onions and garlic flavored croutons to perform this function

• Sorbitol helps maintain the smooth consistency of candies and fudges

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HACCP Principles and Produce Operations

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Produce Associated Foodborne Illness

According to the Centers for Disease Control and Prevention, the number of produce-related outbreaks per year doubled between the periods 1973-1987 and 1988-1992

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HACCP Background

• HACCP system for food safety was first developed by food processors in cooperation with NASA in the 1960’s to ensure the safety of space foods

• Food microbiology, risk assessment and QC principles were joined to form the HACCP system

• The low acid food industry utilized HACCP in the 1970’s in cooperation with the FDA to ensure the quality of low acid canned foods

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Hazard Analysis Critical Control Point (HACCP) Program

• Is a systematic approach to the identification, evaluation, and control of food safety hazards, from raw material production and procurement to distribution and consumption of the finished product (NAC-MCF, 1997)

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The 5 Pre-HACCP Steps

• Bring together your HACCP resources• Describe the product and its method of

distribution• Develop a complete list of ingredients and raw

materials• Develop a process flow diagram• Meet the regulatory requirements for sanitation

standard operating procedures

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HACCP is Based on Seven Principles

1. Conduct a hazard analysis

2. Determine the critical control points

3. Establish critical limits

4. Establish monitoring procedures

5. Establish corrective actions

6. Establish verification procedures

7. Establish record-keeping and documentation procedures

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Quality and Safety Begins in the Field

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HACCP Principle #1

• Assessment of hazards and risks associated with growing, harvesting, raw materials and ingredients, processing, manufacturing, distribution, and marketing, preparation and consumption of the food

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Potential Hazards to be Monitored

• Microbiological: E. coli, coliforms, aerobic plate count, Salmonella, Listeria, foodborne viruses

• Chemical: pesticides, detergent cleaners, chlorine residue

• Physical: insects, wood, glass, sand, rocks, metal

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HACCP Principle #2• Determine the critical control points (CCP)

required to control the identified hazards

• All hazards identified by the hazard analysis must be controlled at some point

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Examples of CCP’s • Raw product temperature

• Storage temperature

• Chlorination

• Sanitation

• Employee hygiene & GMP audits

• Foreign objects

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Monitoring Water Chemistry

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Gloves and Hand Washing

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HACCP Principle #3• Establish the critical limits which must be

met at each identified CCP

• Critical limits are tolerances established beyond which the related CCP is out of control and a potential hazard can exist

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Examples of Critical Limits• Storage temperature (32-40oF for

vegetables)

• Chlorine levels (50-100 ppm)

• Sanitation procedures (frequency)

• Microbiological standards (zero salmonella)

• Residual chlorine (1 ppm)

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HACCP Principle #4• Establish procedures to monitor CCP

• Procedure should be reliable enough to indicate that the hazard is under control

• Due to short shelf life of pre-cut produce, monitoring procedures should be performed quickly

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Examples of Monitoring Procedures for CCP’s

• Thermometer calibration

• GMP audits

• Sanitation swab testing

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HACCP Principle #5• Establish corrective action to be taken

when there is a deviation identified by monitoring of a CCP

• Corrective action must eliminate the hazard which has resulted by deviation from the HACCP plan and must demonstrate that the CCP has been brought under control

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HACCP Principle#6• Establish effective recordkeeping systems

that document the HACCP program

• The HACCP plan should be on file at the processing plant and it should include documentation relating to CCP and any action on critical deviations and disposition of product

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Examples of Records in a HACCP Program

• Ingredients: supplier certification, audit records, storage time & temperature recorders

• Product safety: safe shelf life records, microbiological records, records relating to adequacy of processing procedures

• Processing: records of all monitored packaging CCP, including seal quality and compliance with packaging material specifications

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Examples of Records in a HACCP Program

• Storage and distribution: records on temperature/truck cleanliness

• Deviation file: records of any deviation to the HACCP plan

• Only those records pertaining to CCP must be available to regulatory agencies at their request

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HACCP Principle #7• Establish procedures for verification that

the HACCP system is working correctly• Verification consists of methods,

procedures and tests used to determine that the HACCP system is in compliance with the HACCP plan

• Verification confirms that all hazards in produce processing are identified in the HACCP plan

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Examples of Verification Activities

• Periodic review of HACCP

• Review of HACCP records

• Review of deviations and dispositions

• Random sample collection and analysis

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SUMMARY

• This module has briefly covered food quality assurance, plant sanitation, GMPs, cleaning and disinfection methods, quality factors and standards, flavor and color determination, food additives and HACCP.

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