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. 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

4. Fluid Milk

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. Butterfat: Cream
Comes from the separator with a fat content of
35-45%
Used for further processing in the dairy industry
—ice cream, butter

15. 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

16. 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

17. 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

18. 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

19. 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

20. Milk Products and By-
Products

21. Milk Products and By-Products
Include
Butter
Concentrated and dried milk
Cheese
Whey products
Yogurt
Fermented products
Ice Cream

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. Cheese Making Steps
Treat milk
Additives
Inoculation and milk ripening
Coagulation
Enzyme
Acid
Heat-acid
Curd Treatment
Cheese ripening