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MILK

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... areas daries are 1,000 cows or more Milk fresh from the cow is virtually sterile Post handling must maintain the milks ... fermented milk product Originated ... – PowerPoint PPT presentation

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Title: MILK


1
MILK
2
Objectives
  • Define the term milk
  • Describe quality control during the production of
    milk and milk products
  • Explain pasteurization and homogenization
  • Identify three methods of pasteurization
  • Describe the solids composition of milk
  • Discuss the separation of butterfat and its use
  • List four beverage milk products
  • Describe butter
  • Name 5 concentrated or dried dairy products
  • List the steps in the cheese making process
  • Identify 3 bacteria used to produce dairy
    products
  • Name 5 fermented dairy products
  • List the steps in making and ice cream and make
    ice cream
  • Describe the USDA quality grade shields

3
Terms To Know
  • Buttermilk
  • Churning
  • Coalesce
  • Curd
  • HTST
  • Lipolysis
  • LTLT
  • Rennet
  • Ripening
  • Ropey
  • Solids-not-fat
  • Standard plate count (SPC)
  • standardized
  • Ropey
  • Solids-not-fat
  • Standard plate count (SPC)
  • standardized
  • Thermization
  • UHT
  • Ultrapasteurization
  • Vaccum evaporation
  • Whey

4
Introduction
  • Milk the first food for young mammals
  • Provides high quality protein, vitamins and
    minerals and is a source of energy
  • Worldwide many mammilian species are used to
    produce milk and milk products
  • Goats, sheep, horses, yaks
  • However, our focus will be on milk from dairy cows

5
Fluid Milk
6
Fluid Milk
  • Collodial dispersion of the protein caesin and
    the whey proteins. It is an emulsion with fat
    globules suspeneded in the water phase
  • Composed mainly of water
  • 87-89
  • Milk solids make up the other 12-13
  • Solids include the carbs, lactose, fat, protein
    and minerals
  • Solids-not-fat
  • Excludes the fat and includes the caesin, whey,
    lactose, proteins, minerals

7
Production Practices
  • Fewer cows are producing more milk
  • Daries are becoming larger
  • In major production areas daries are 1,000 cows
    or more
  • Milk fresh from the cow is virtually sterile
  • Post handling must maintain the milks nutritional
    value and prevent deterioration caused by
    physical and biological changes
  • Equipement must be maintained to government and
    industry standards

8
Production Practices
  • Cows are milked twice a day
  • Some farms milk 3-4 times/day
  • Milk is immediately cooled from the body
    temperture of the cow to below 41 degrees F
  • It is then stored at the farm under refrigeration
    until it is picked up by tanker trucks at least
    every other day
  • A sample of the milk is collected at this time
    for later lab analysis

9
Quality Control
  • On the farm
  • Inspectors monitor herd health, farm water
    supply, sanitation, milk temperture, holding
    times, bacteria counts
  • Violations of health standards result in heavy
    penalties up to and including suspension from
    business
  • Inspections occur both at the farm and processing
    plants on a regular on-going basis
  • Inspectors have full authority to suspend plant
    operations in order to conduct detailed
    examinations of all equipment, facilities and
    products
  • The dairy industry works hard to ensure that they
    comply with or exceed all regulations

10
Quality Control
  • Finished dairy products
  • Tested regularly by state inspectors to ensure
    compliance with
  • Standards of Identity
  • Refers to criteria such as mouisture, butterfat,
    protein content
  • Purity
  • Refers to pathogens and residues criteria
  • The Food and Drug Administration (FDA) sets the
    standards of identity for beverage milk products

11
Processing
  • When milk arrives at the plant it is checked to
    make sure that it meets the standards for
    temperture, total acidity, flavor, odor, tanker
    cleanliness and absence of antibiotics
  • Butterfat and solids-not-fat content is analyzed
  • These amounts will vary with the feed, breed of
    cow and time of year
  • These are also used along with the volume to
    determine what the producer will be paid
  • Once the milk passes these receiving test it is
    pumped into large refrigerated silos

12
Pasteurizing
  • Heating the raw milk to kill all pathogenic
    microoranisms that may be present
  • Not sterilization
  • After pasteurization some harmless bacteria may
    still be present
  • these are the bacteria that cause milk to go
    sour
  • Refrigeration is the best way to slow the growth
    of these organisims

13
Pasteurizing
  • Low Temperture Longer Time (LTLT)
  • Heats milk to at least 145 degrees F for at least
    30 minutes
  • Can cause a cooked flavor
  • Not used by some milk plants for fluid milk
    products
  • High Temperture/Short Time (HTST)
  • Heats milk to at least 161 degrees F for at least
    15 seconds
  • Milk is immediately cooled to below 40 degrees F
    and packaged in plastic jugs or plastic coated
    cartons
  • Ultrapasteurization
  • Heating milk to 280 degrees F or higher for 2
    seconds followed by rapid cooling to 45 degrees
    or less
  • Ultrahigh Temperture Processing
  • Sterilizes the milk
  • Heats it to 280-302 degrees for 2 to 6 seconds
  • Milk is aseptically packaged and does not require
    refrigeration until it is opened

14
Butterfat
  • Several different types of product
  • Whole milk, 2, 1, nonfat, Half Half
  • Seperated using separator that separates the
    cream and skim portions of the milk
  • For example During the separation of whole milk
    two streams are produced the fat-depleted
    stream, which the above mentioned beverage milks
    are made of skim milk for evaporation and/or
    drying and the fat-rich stream, the cream

15
Butterfat Cream
  • Comes from the separator with a fat content of
    35-45
  • Used for further processing in the dairy
    industryice cream, butter

16
Homogenization
  • Prevents the cream from rising to the top
  • A homogenizer forces milk under high pressuure
    through a valve that breaks up butterfat globules
    to such a small size that they will not coalesce
    (stick together)
  • Does not affect the nutrion or quality

17
Beverage Milk
  • Most raw milk fat content is 4 or higher
  • Most beverage milk is 3.4
  • Lower fat contents- 2, 1, Skim
  • These products are produced by partial or
    complete skimming and then adding cream back to
    achieve the final desired fat content

18
Nutritional Qualities
  • Vitamins may be added
  • A D most often due to their loss
  • A during fat separation and heating
  • D because it is not present in milk
  • Supplemeted in the form of a water-soluble
    emulsion
  • Many states have milk standards that require the
    addition of milk solids
  • These represent the natural mineral, protein, and
    sugar portion of nonfat dry milk

19
Quality Control
  • Numerous test on raw and paterurized product
  • Microbial organisims are tested for using the
    standard plate count (SPC) and ropey milk test
  • Equipment used to analyze butterfat and
    solids-not-fat is calibrated on a regular basis
    to ensure consistency
  • All products have a sell-by date
  • Samples of the products packaged each day are
    saved to confirm they maintain their freshness 7
    days after the sell-by date

20
Packaging
  • Once milk is separated, standardized, homogenized
    and pasteurized it is held below 40 degrees F
  • Then it is packaged into gallon, ½ gallon, quart,
    pint and half pint containers
  • Packaging machines are maintained under strict
    standards
  • All equipment is washed daily
  • Automatic clean-in-place systems guarantee
    consistent sanitation with minimum manual
    handling to reduce the risk of contamination
  • Once packaged the products are conveyored to cold
    storage where they are stored for a short time
    before being shipped to supermarkets where they
    are kept in cold storage or refrigerated display
    cases

21
Milk Products and By-Products
22
Milk Products and By-Products
  • Include
  • Butter
  • Concentrated and dried milk
  • Cheese
  • Whey products
  • Yogurt
  • Fermented products
  • Ice Cream

23
Butter
  • Made by churning pasteurized cream
  • Churning breaks up the fat globule membrane
  • This breaks the emulsion, fat coalesces and the
    water (buttermilk) escapes
  • Federal law requires that it contain at least 80
    milkfat, nutritionally butter is a fat.
  • Salt and coloring may be added
  • Today commercial butter making is a product of
    knowledge and experience gained over the years

24
Butter Make-Up
  • Normal Salted Butter
  • Fat 80-82
  • Water 15.6-17.6
  • Salt 1.2
  • Proteins, Calcium, Phosphorous 1.2
  • Also contains fat soluble vitamins A, D, E

25
Butter
  • Should have uniform color
  • Be dense
  • Taste clean
  • Water should be dispersed in fine droplets so
    that the butter looks dry
  • Consistency should be smooth so that it is easy
    to spread and melts readily on the tongue

26
Making Butter
  • From storage tanks the cream goes to
    pasteurization
  • This destroys enzymes and microorganisms that
    would impair the keeping quality of the butter
  • Next, ripening
  • Here the cream is subject to a program of heat
    treatments designed to give the fat the necessary
    crystaline structure so it solidifies on cooling
  • Takes 12-15 hours
  • Churning
  • Cream is violently agitated
  • This breaks down the fat globules, causing the
    fat to coagulate into butter grains, leaving the
    liquid part (buttermilk)
  • Butter is salted and worked to ensure even
    distribution
  • Packaged
  • Sent to cold storage

27
Butter Churns From the Past
28
Todays Butter Churn
29
Concentrated and Dried Dairy Products
  • Concentrated products have partial water removal
  • Dried products have water removed to less than 4
  • Benefits of both products are
  • Increased shelf life
  • Convenience
  • Product flexibility
  • Decreased transportation costs
  • Storage

30
Concentrated and Dried Dairy Products
  • Concentrated Products
  • Evaporated skim or whole milk
  • Sweetened condensed milk
  • Condensed buttermilk
  • Condensed whey
  • Dried Products
  • Milk Powder
  • Whey Powder
  • Whey Protein concentrates

31
Cheese
  • Traditionally cheese was made as a way of
    preserving the nutrients of milk
  • Cheese- the fresh or ripened product obtained
    after coagulation and whey seperation of milk,
    cream, or partly skimmed milk, buttermilk or a
    mixture of these
  • THOUSANDS of varieties

32
Cheese Making Steps
  • Treat milk
  • Additives
  • Inoculation and milk ripening
  • Coagulation
  • Enzyme
  • Acid
  • Heat-acid
  • Curd Treatment
  • Cheese ripening

33
Yogurt
  • Semisolid fermented milk product
  • Originated in Bulgaria
  • Milk from a variety of animals is used in yogurt
    production but most of the industrialized nations
    use cows milk
  • Starter culture used in most yogurt production is
    a blend of Streptococcus salivarius thermophilus
    (ST) and Lactobacillus delbruekii bulgaricus (LB)

34
Making Yogurt
  • Milk is clarified and separated into cream and
    skim milk
  • Standardized to achieve the desired fat content
  • Various ingredients are blended together in a mix
    tank equipped with a power funnel and an
    agitation system
  • Mixture is then pasteurized
  • Once the homgenized mix has cooled to an optimum
    growth temperature, the yogurt starter culture is
    added

35
Fermented Milk Beverages
  • Cultured Buttermilk
  • Once a by-product of butter production, now
    produced from whole or skim milk
  • Acidophilus Milk
  • Traditional milk fermented with LA which is
    thought to have therapeutic benefits in the
    gastrointestinal tract
  • Sour Cream
  • Others

36
Ice Cream (start)
  • Greater than 10 milk fat by legal definition
  • As high as 16 fat in some premium ice cream
  • 9-12 milk solids-not-fat
  • Also contains 12-16 sweeteners-usually a
    combination of sucrose and glucose-based corn
    syrup sweeteners
  • 0.2-0.5 stabilizers and emulsifiers
  • 55-64 water from the milk or other ingredients
  • When frozen about half the volume of ice cream is
    air
  • All ice cream is made from a basic white mix

37
Basic Steps In Manufacturing Ice Cream
  • Blending of the mix ingredients
  • Pasteurization
  • Homogenization
  • Aging the mix
  • Freezing
  • Packaging
  • Hardening

38
Quality Products
  • Established by USDA
  • Grades are used to describe different grades of
    quality in butter, cheese (Cheddar, Colby,
    Monterey, Swiss)
  • FDA established the Grade A designation for fluid
    milk products, yogurt and cottage cheese
  • Grade standards are used to
  • Identify levels of quality
  • Provide a basis for establishing prices at
    wholesale
  • Supply Conumers with a choice of quality levels

39
Milk Substitutes
  • Margarine
  • Frozen desserts
  • Coffee whiteners
  • Whipped toppings
  • Soy milk
  • All are made by combining nondairy fats with
    certain classes of milk components

40
Reduced Fat Products
  • Brought on to the market in the effort to reduce
    calories, saturated fat, cholesterol
  • When fat is replaced the replacement must perform
    the same functions as the fat.
  • It must give the product the same texture or
    mouth feel
  • Why?
  • What would consumer repsonse be if it didnt?

41
Summary
  • Milk provides high quality protein, energy,
    vitamins, minerals
  • Dairy industry provides a variety of milk
    products
  • USDA and FDA maintain quality standards
  • Milk is pasteurized to protect consumers against
    pathogens
  • Milk is homogenized to keep milk fat in
    suspension
  • Butterfat is separated from the milk to be added
    back in in the desired amounts
  • Concentrated and dried products increase shelf
    life and convenience and decrease transportation
    costs
  • USDA established grade standards for butter,
    cheese and instant nonfat dry milk
  • FDA established grade designations for fluid
    milk, yogurt, cottage cheese
  • Only officially graded products carry a grade
    shield
  • In an effort to meet consumer demands the food
    industry has developed milk and milk substitutes
    and reduced fat products

42
Lab
  • Making Butter

43
STUDENT ACTIVITY
  • Develop a presentation comparing BUTTER to
    MARGARINE
  • Compare their make-up (ie-butter is made from
    milk fat and margarine is made from vegetable
    oil)
  • Compare their healthfullness
  • Find pictures
  • Make a poster
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