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
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
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
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
