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  • Luke Howard
  • Professor
  • Food Science Department
  • University of Arkansas

  • This module represents a brief overview of the
    course FDSC 4203 Quality Evaluation and Control
    taught by Dr Luke Howard at the University of
  • It is narrated by Dr Steve Seideman, Extension
    Food Processing Specialist of the Institute of
    Food Science Engineering, University of

  • 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

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)
Quality Assurance
  • Modern term used for describing the control,
    evaluation and audit of a food processing system
  • Its primary function is to provide confidence
    for management and the ultimate customer
  • The customer establishes the level of quality the
    firm must manufacture

Canning Quality Assurance
Quality Control
  • A large part of a QA program is built around
    quality control
  • Quality control means to regulate to some
  • It is an important tool for the production worker
    to help operate the line in conformance with the
    predetermined parameters for any given quality

Quality Evaluation
  • Is also part of a QA operation
  • It is used to describe or appraise the worth of a
  • 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

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

  • Makes a product what it is, varies among
  • 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

Standards for Quality
  • Legal standards
  • Company or voluntary label standards
  • Industry standards
  • Consumer or grade standards

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
  • Requires training and experience

Objective Methods for Determining Quality
  • Physical - size, texture, color, consistency,
    imperfections, headspace, drained weight, vacuum
  • Chemical - enzyme conc., moisture, fiber, pH,
  • Microscopic - used for adulteration and
    contamination, and differentiation between cell
    types, tissue types and microorganisms

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 gt profits

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

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)

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

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

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

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

Specialized Equipment for QE
  • Colorimeter
  • pH meter
  • Refractometer
  • Viscometer
  • Moisture analyzer
  • Microscope

Factors Affecting Quality
  • Cultivar
  • Maturity
  • Cultural practices
  • Harvesting and handling
  • Processing
  • Shelf-life
  • Use

Food Plant Sanitation
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 persons job in the plant

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

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

Plantkeeping - Building
  • Floors water tight, smooth surfaced, and sloped
    1/8 to 1/4 per foot to floor drains every 10
  • 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
  • Good lighting, ranges from 25 to 150 foot candles

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
  • 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)

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
  • Policy of FIFO should be strictly adhered to

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
  • Observe proper habits of cleanliness

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

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

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.

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

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

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

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

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

  • Chemical supplier can assist in plant audit for
    developing a sanitation program
  • Supplier can outline specific cleaning methods,
    products, and exact amounts, times and temps
  • 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

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

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.
Challenges for Food Sanitation
  • Increasing number of older consumers
    (immuno-compromised individuals)
  • New products and processes (egs MAP, sous vide,
    aseptically packaged foods
  • high pressure, pulsed electric fields)
  • Sanitation programs are a prerequisite for HACCP

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
  • Positive air pressure should be maintained

Plant Design
  • Raw materials should be isolated from processed
  • 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

Plant Design
Plant Design
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
  • The application of sanitizers to prevent
    recontamination before processing

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

Rinsing Step
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

Alkaline Detergents
  • Compounds used for removal of organic soils, such
    as oils, grease, proteins and carbohydrates
  • Strongly alkaline compounds (pH gt 13) egs NaOH
  • Moderately alkaline compounds (pH 10-12) egs
    sodium metasilicate
  • Mildly alkaline compounds (pH 7-12) egs sodium
    carbonate and sodium sesquicarbonate
  • Complex phosphates egs TPP, SHMP

Acid Detergents
  • Compounds for removal of encrusted soils and
    deposits formed from application of alkaline
  • Strong inorganic acids egs hydrofluride,
    hydrochloride (scale removal in boilers, are
    corrosive to stainless steel)
  • Organic acids egs citric and hydroxyacetic acids
    (used in manual cleaning formulations, also
    function as water softeners)

Detergent Auxiliaries
  • Incorporated with cleaning compounds to improve
    their performance, provide filler material or
    bulk, condition water and protect sensitive
  • Surfactants are organic compounds used in both
    alkaline and acidic formulations to increase soil
    penetration, improve rinsing, or to control
  • Sequestrants combine with magnesuim and calcium
    salts egs SPP, EDTA, sodium gluconate

  • Soil should be completely removed prior to
    sanitizing You cant sanitize a dirty surface
  • Efficacy is affected by time, pH, temperature,
    concentration, water hardness and surface
  • 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

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

Important Properties of Sanitizers
  • Ability to provide a rapid antimicrobial activity
    against a range of organisms
  • Be readily available, inexpensive and ready to
  • 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

  • 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

Chlorine Reaction in Water
  • Cl2 H2O HOCL H Cl-

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

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)

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

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

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

Equipment and SystemsManual Aids
  • Brushes should have a block constructed of
    durable material resistant to heat, chemicals and
  • Bristles should be nylon, with good water holding
    capacity to carry cleaning solution to contact
  • Scrapers and scouring pads should be used to
    remove baked-on deposits and encrusted soil from
    equipment and other surfaces

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

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

Foam Cleaning System
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

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

Clean-In-Place System
Sanitizer Application Equipment
  • Portable pressure sprayers
  • Centralized systems can provide consistent
    sanitizer concentration and convenient hookups

Factors Affecting Sanitizer Efficacy
  • Initial microbial load on raw product
  • Water quality, chemistry and temperature
  • Biofilm formation
  • Concentration, temperature and contact time of
  • Organic matter content on the product and in the

Quality Factors and Standards
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
  • Curvature of cucumbers for pickling

Size and Color Sorting
Weigh Grading
Color Sorting
Color Sorting
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
  • Color of a food foam or batter varies with the
    density and can indicate a change in mixing

Food Color
Color Measurement
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

Hunter Color Solid
Color Wheel
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

Gloss Meter
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,
  • Used for ketchup, honey, syrups, purees

Viscometers On-Line
Rheological Properties
On-Line NIR for Chemical Analysis
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.

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

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

Texture Analyzers
Texture Analyzers
Texture Profile Analysis
Texture Profile Analysis
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

Odor Determination
Electronic Nose for QC
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

Sensory Analysis
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
  • Keeping quality - shelf life studies, ASLT

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

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 gt 100
    foods (meat, dairy, poultry, fruits, vegetables,

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,

USDA Standards of Composition and Identity
  • Minimum content requirements for federally
    inspected meat and poultry products (canned or
  • 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

FDA Standards of Identity
  • Establishes what a given food product is
  • Example - what a food must contain to be labeled
  • Includes both mandatory ingredients and optional

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

(No Transcript)
Flavor Determination
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

Basic Taste Attributes
  • Salty
  • Sweet
  • Sour
  • Bitter

  • Strictly tongue taste, not flavor
  • Taste originates from compounds in solution
  • All taste buds can detect all four qualities, but
    some respond to one quality better than the other

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

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

Sweet Quality
  • Is elicited by a variety of food related organic
  • Most common sweetners are sugars, which vary
    considerably in sweetness
  • Based upon equimolar solutions
  • fructose gt sucrose gt maltose gt glucose gt
  • Sweetness is affected by concentration, food
    medium, and temperature of food medium

Bitter Quality
  • Is difficult to associate with a specific
  • Most prominent class of bitter tasting compounds
    are the alkaloids (caffeine, quinine and
  • Other include heavy halide salts, amino acids and

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

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

Food Smell or Aroma
Color Determination
  • 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

  • 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

  • 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

Fates of Light When Illuminated
  • Reflected
  • Transmitted
  • Absorbed
  • Refracted

Color Perception
  • If all light is reflected from an opaque surface,
    the object appears white
  • Is some light is absorbed, the object appears
  • If all light is absorbed, the object appears black

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

Colors in the Visible Spectrum
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

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

Color MeasurementMunsell System
  • Contains 1225 color chips used for convenient
    visual comparison
  • Each chip has a numerical designation
  • Advantages simple, convenient, easy to
  • 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

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

Spectrophotometric Measurement of Color
  • Early instrumental methods for color measurement
    were based on transmission, or reflection
  • 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

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

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

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Food Additives
History of Food Additives
  • Smoking and sun drying were early methods used
    for food preservation
  • Much of our history is an indirect result of
    mans quest for spices and other flavorings egs
    Marco Polos travels, discovery of America by
    Columbus, Cortez and the vanilla bean
  • Texas settlers in the 1800s - chili powder

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

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

Reasons for Using Food Additives
  • Rapidly expanding population, and migration of
    the population from rural to urban areas
  • With lt 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

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

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

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

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

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

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

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

Coloring Agents
  • Synthetic agents include FDC yellow 5 and red
  • The soft drink industry is one of the prime color

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

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

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

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

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

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

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
    Tangtype drinks
  • Corn starch is added to powdered sugar to keep it
  • Calcium stearate in garlic salt is another
    example of the use of anticaking agents

Leavening Agents
  • A leavening agent is any chemical or biological
    substance that can produce bubbles of gas in
  • These gas bubbles expand, causing the dough to
    rise thus yielding foods which are light in
  • Yeast was originally used, but is not a reliable
    source of gas

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

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

  • 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
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

HACCP Background
  • HACCP system for food safety was first developed
    by food processors in cooperation with NASA in
    the 1960s 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
    1970s in cooperation with the FDA to ensure the
    quality of low acid canned foods

Hazard Analysis Critical Control Point (HACCP)
  • 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)

The 5 Pre-HACCP Steps
  • Bring together your HACCP resources
  • Describe the product and its method of
  • Develop a complete list of ingredients and raw
  • Develop a process flow diagram
  • Meet the regulatory requirements for sanitation
    standard operating procedures

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

Quality and Safety Begins in the Field
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

Potential Hazards to be Monitored
  • Microbiological E. coli, coliforms, aerobic
    plate count, Salmonella, Listeria, foodborne
  • Chemical pesticides, detergent cleaners,
    chlorine residue
  • Physical insects, wood, glass, sand, rocks, metal

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

Examples of CCPs
  • Raw product temperature
  • Storage temperature
  • Chlorination
  • Sanitation
  • Employee hygiene GMP audits
  • Foreign objects

Monitoring Water Chemistry
Gloves and Hand Washing
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

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)

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

Examples of Monitoring Procedures for CCPs
  • Thermometer calibration
  • GMP audits
  • Sanitation swab testing

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

HACCP Principle6
  • 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

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

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

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

Examples of Verification Activities
  • Periodic review of HACCP
  • Review of HACCP records
  • Review of deviations and dispositions
  • Random sample collection and analysis

  • 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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