Processing Dairy Products
Terms
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cattle byproducts
cheddaring
curd
curdling
homogenization
pasteurization
 solids-not-fat (SNF)
 standard plate count
(SPC)
 standardized
 whey
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What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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Milk processing involves many steps.
All farm equipment must be kept and
maintained to government and
industry standards to ensure safe,
healthy, and quality products.
After dairy cows are milked, the
liquid is cooled from the cow’s body
temperature to below 40°F (4°C).
It is refrigerated until the milk tanker driver
arrives to record the amount of milk, make
special notes of the milk temperature and odors,
and transport the product.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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A. At the milk processing plant, samples
are checked for proper temperature, total
acidity, flavor, odor, cleanliness,
and the absence of antibiotics.
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The butterfat and solids-not-fat
are also analyzed.
Solids-not-fat (SNF) contain the
protein, lactose, and minerals and
are the total solid minus the milk fat.
The amounts of butterfat and SNF can vary
because of cow breed, feed supply, and the
time of year.
Many producers depend on these counts for
contract payments.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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B. Within 72 hours, the milk must be
processed.
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The milk is pasteurized at the processing plant.
1. Pasteurization is the process of heating the
milk to destroy all pathogenic bacteria. Milk can
be pasteurized by heating it to 161°F (72°C)
for 15 seconds.
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Then the milk is immediately cooled below 40°F
(4°C).
2. Ultrapasteurization is used to extend the
shelf life of refrigerated products and to enable
products to be kept at room temperature.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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C. Milk is then standardized.
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Milk is processed through
centrifugal separators to create
a skim portion and a cream
portion.
Most milk in the United States is standardized.
The cream portion is added back to the skim
portion based on the desired fat content for the
product.
Water is never added to lower the butterfat.
The extra cream from this step is used to make
ice cream or butter.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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1. Common products/types of fluid milk
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a. Whole milk
b. Low-fat milk
c. Skim milk
d. Flavored milk
2. Major types of milk
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a. Fluid milk
b. Manufactured milk products (evaporated
milk and sweetened condensed milk)
c. Powdered milk
d. Specialty milk (multi-vitamin, lactosetreated, or low-sodium)
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?

D. Homogenization is
the process used to
prevent the cream from
rising to the top of a
finished milk package.
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Homogenization reduces the
milk fat globule size,
allowing for even distribution
in milk.
This process does not affect
the nutrition or quality of the
product; it keeps the final
product from forming a
cream topping.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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E. Vitamin quantities are often reduced as a result
of the heating process and the removal
of butterfat, so milk is commonly
fortified with vitamins A and D.
1. Vitamin A is a fat-soluble vitamin.
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a. Whole milk is known as a good source of
vitamin A because of the higher fat content.
b. There are lower quantities of vitamin A in 2 percent, 1
percent, and skim milk.
2. Vitamin D is also a fat-soluble vitamin that
occurs naturally in milk at low levels.
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a. The process of vitamin D fortification started in the
1930s to reduce the occurrence of rickets in children.
b. Today, vitamin D is necessary for human health.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?

F. Quality control is conducted through all of the
steps in milk processing.
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1. A standard plate count (SPC) is performed
to determine the total number of bacteria for a
specific amount of milk.
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Numerous tests and samples are gathered to analyze the
presence of microbiological organisms.
This test is used in the grading procedure.
2. Milk can be Grade A or Grade B. (Grades are
not the same as classes of milk.)
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a. Grade A milk meets the sanitary standards for fluid
milk products and can be used for any dairy product.
b. Grade B milk is considered a manufacturing grade.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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G. Classification is used for pricing
systems.
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Producers may participate in the Market Order
Program, which establishes prices
according to milk uses.
1. Class I milk is the highest price
class and is used for fluid milk
products.
2. Class II is used for soft milk
products like yogurt, cottage cheese,
and ice cream.
3. Class III is used for hard cheeses.
4. Class IV is used for butter and for milk
products in dried form.
What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?
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H. Milk products will contain a sell-by date on the
finished product package.
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This refers to the last date on which the product can be
offered for sale.
I. When the product has completed all of the
steps in processing, pasteurization,
standardization, homogenization, and quality
control, it is packaged into gallon, half-gallon,
quart, pint, and half-pint containers.
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These containers are kept below 40°F (4°C) in storage
warehouses where they are stored for a short period of
time and then shipped to supermarkets.
How do you evaluate milk samples for
flavor and odors? How do you critique
milker head units for defects?
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The flavor, scent, and visual inspection of milk are
important to the overall quality and can be
affected by the cow’s health, consumed feed,
bacteria, chemical changes, or absorption of
foreign flavors after processing.
The process of judging and scoring milk
and other milk products is consistent
throughout processing.
Milk is checked for irregularities at
various points, including storage.
Dirty equipment can impact the results, so
sanitation is critical.
These quality control practices ensure safe,
healthy, and delicious milk products.
How do you evaluate milk samples for
flavor and odors? How do you critique
milker head units for defects?
A. Determining problems
 1. An off-flavor can be found by smelling
the open container rather than a small
sample.
 2. The next step involves tasting the milk.
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Samples should be at room temperature.
The colder the sample, the harder it is to
distinguish certain flavors.
The major flavor defects are bitter, feed, flatwatery, foreign, garlic/onion, high acid, malty,
oxidized, rancid, salty, and unclean.
How do you evaluate milk samples for
flavor and odors? How do you critique
milker head units for defects?
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B. The cleanliness of milking machine parts can
influence the milk flavor.
These are the possible defects of rubber parts:
1. Dirty or milk stone—These parts have evidence
of gray and/or chalky soil or light films of soil.
2. Checked or blistered—These parts have been
used too long and have been poorly cleaned.
3. Leaky parts—These parts will allow air into the
system due to holes in air hoses.
4. Poorly fitted parts—These parts are obviously
not designed to fit and may include split hoses or
broken hoses that are too short.
How do you evaluate milk samples for
flavor and odors? How do you critique
milker head units for defects?
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C. These are the possible defects of metal parts:
1. Dirty or milk stone—These parts show evidence
of soil or chalky material.
2. Badly dented or damaged—These parts have
damage that is sufficient enough to interfere with
the function of the parts and with
cleaning/sanitizing them.
3. Pitted or corroded—These parts have evidence
of rust and darkened surfaces.
4. Open seams—These parts have evidence of
broken joints, heads, or screws.
What are the steps in the cheese-making
process? What are the four groups of
cheese?
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The varieties of cheese are based on ingredients,
processing steps, and characteristics
of the finished product.
A. Cheese can be made from a
combination of fluid milks.
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Cottage cheese is made from skim milk;
Swiss cheese is made from a mixture of whole and skim
milk; and cheddar cheese is made from whole milk.
B. Cheese is made by removing most of the milk
solids from the milk through a process called
coagulation or curdling.
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Curdling is the process that causes the milk to form into
curd—the part of milk that coagulates when milk turns
sour or is treated with enzymes.
What are the steps in the cheese-making
process? What are the four groups of
cheese?
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1. First the milk is heated.
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Then a liquid starter culture is added.
The bacteria from the culture will form acids in the milk,
causing the milk to sour.
2. Rennet is added to force the milk to thicken.
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It contains the enzyme rennin and is found in the
stomachs of young calves.
Other enzymes may be used in the process. After the
mixture is stirred, the curd forms.
The curd is separated from the whey (the watery liquid
part of the milk mixture in the cheese-making process)
by heating and draining it.
What are the steps in the cheese-making
process? What are the four groups of
cheese?
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C. The next step may involve
texture of the curd.
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D. Dry salt or brine is used next to achieve
a desired flavor.
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This step is also called cheddaring;
it helps to force out more whey and allows for
fermentation to continue until a desired pH
level is reached.
For example, the curd of mozzarella is formed
into laves and placed into a brine, salt-water
solution.
E. Cheese is formed into blocks.
What are the steps in the cheese-making
process? What are the four groups of
cheese?
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F. The ripening or curing of
cheese is exposed to a
temperature/humidity controlled
environment for a specified
duration.
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Different types of cheese require months or
years to age.
The changes that occur during the curing/aging
process depend on the enzymes, bacteria,
mold, yeast, or combination of these agents.
G. After the cheese has met the desired
age, it may be cut, packaged, waxed (if
necessary), and put into blocks.
What are the steps in the cheese-making
process? What are the four groups of
cheese?
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H. Cheese can be grouped as very hard,
hard, semi-soft, or soft.
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The type of cheese depends on the kind of milk
used, the methods used in the coagulating of
milk, the cooking and forming of the curd, the
type of culture used, the salting method, and
the ripening conditions.
A soft cheese, like cottage cheese, is an
unripened cheese with 80 percent moisture.
Parmesan and Romano are very hard cheeses
(grated or shaker cheeses).
How do you identify samples of
cheese?
Cheese identification should be
based on body, texture, color,
and flavor.
 A. Body refers to the physical properties.
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Observing and feeling the firmness,
cohesiveness, elasticity, and plasticity will help
to determine and describe the appearance.
B. Texture refers to how the cheese
particles are bound together.
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Open textures show spaces between the
particles; in contrast, closed textures show
very few openings.
How do you identify samples of
cheese?
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C. Color can range from a cream or offwhite to a light or heavy yellow.
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The color should only act as a guide
when identifying cheese.
D. Flavor is the final factor.
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The use of taste and smell help to distinguish
the cheese types.
Cheeses have specific scents.
Noting the odors and tasting small pieces will
assist in identification.
What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
Yogurt, sour cream, and cottage cheese
products are handled under controlled
conditions.
 These products require the addition of
bacteria cultures to fluid milk for
fermentation to occur.
 These bacteria cultures will convert lactose
into lactic acid.
 The fermentation process and the specific
bacterial culture used will determine the
end product.
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What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
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A. Yogurt products may use whole milk,
low-fat milk, or skim milk, depending on
the type of product desired.
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Yogurt must contain at least 3.25 percent milk fat.
Low-fat yogurt allows up to 2 percent milk fat, and
nonfat yogurt allows less than 0.5 percent milk fat.
Stabilizers (e.g., alginates, gelatins, and starch) are used
to improve the body and texture by increasing firmness
and preventing whey separation; they also help to keep
the fruit in yogurt uniformly mixed.
Flavors, sweeteners, and fruit may be added to yogurt
for variety.
Bacterial cultures are used to ferment lactose so lactic
acid results, producing the characteristic yogurt flavor.
What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
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The general steps in the yogurt-making process
are listed below.
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1. The milk composition should be adjusted and the
ingredients blended.
2. The milk mixture should be pasteurized.
3. Homogenizing the milk ensures that all of the
ingredients are thoroughly mixed.
4. The product is cooled at 108°F (42°C)—the ideal
growth temperature for a starter culture.
5. The product should be inoculated with a starter culture
and mixed into the cooled milk.
6. The product is then held at 108°F (42°C) until a pH of
4.5 is reached.
7. The yogurt is cooled to 44°F (7°C) to stop the
fermentation process.
8. Fruit and flavors are added.
9. The finished product is ready for packaging.
What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
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B. Sour cream can be offered as regular,
reduced-fat, or nonfat.
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Regular sour cream contains at least 18
percent milk fat and is made from light cream.
Reduced-fat sour cream contains at least 25
percent less milk fat than regular sour cream
and is made from half-and-half.
Nonfat sour cream contains no more than 0.5
grams of milk fat per serving.
Sour cream may be cultured or acidified light
cream.
What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
Steps to culture sour cream are as follows:
 1. First, the culture (Streptococcus lactis)
is added to pasteurized light cream.
 2. Then it is incubated at 72°F (22°C) until
the desired flavor and the desired
thickness are reached.
 3. Additional nonfat milk solids and
stabilizers are added, as needed.
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What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?
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C. Cottage cheese is considered a fresh, unripened, soft
cheese with a mild and slightly acidic flavor.
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Four types of cottage cheese exist: creamed
cottage cheese, low-fat cottage cheese, nonfat
cottage cheese, and baker’s cheese.
The following are steps in the creation of
nonfat cottage cheese:
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1. A bacterial culture or food-grade acid (vinegar) is added to
pasteurized milk.
This causes the separation of the milk solids from the whey.
2. The curds are formed and gently cut into pieces that allow
the whey to be drained.
3. The curds are cooked and pressed to force out more whey.
4. The curds are rinsed, and salt is added.
5. Light cream dressing is added to achieve the desired finished
product.
What are the steps in the buttermaking process? What are the types of
butter?
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Butter is made from pasteurized cream and
comes in several types.
A. Making butter involves several steps.
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1. The cream is churned or shaken until the
milk fat/butterfat is separated from the
buttermilk.
2. After churning, the butter is rinsed and salted (if desired).
3. The excess buttermilk is removed.
B. There are several types of butter products.
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1. Traditional butter is made from a sweet cream (also known
as pasteurized cream), has salt added for flavor, and acts as a
preservative.
2. Unsalted butter is also available.
3. Whipped butter is another product.
4. Clarified butter is made from regular butter; however, the
water is evaporated as it is heated slowly.
5. Cultured butter is produced from a churned cream that has
been soured by a lactic acid culture.
What are the marketing options for
dairy products?
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Even though the dairy industry is probably best
known for milk production, several additional
items are used to generate dairy farm income.
A. Milk production is important to the economy
because milk is used in many products.
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In terms of nutrition, milk is one of the least expensive
products.
B. Veal is the meat of young calves that are not
used for replacement animals in the dairy herd.
C. Beef is the meat from cattle.
D. Cattle byproducts are products made from
various cattle parts.
What is the difference between real
and artificial dairy foods?
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Many foods are made as imitation or substitute
products, and these products do not contain the
same nutrients as the real products.
A. The main difference in imitation dairy products
is the lack of real milk as the base product.
Imitation dairy products can be found in:
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1. Cheese—Colby, cheddar, cream, mozzarella, and
American pasteurized processed cheese
2. Butter
3. Cream
4. Whipped cream
5. Sour cream
6. Ice cream
7. Milk
What is the difference between real
and artificial dairy foods?
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B. Imitation or artificial foods do not provide the
nutrients of the traditional products.
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1. These products are inconsistent because the
ingredients can be changed whenever desired by the
manufacturers.
2. These products lack milk as the base product.
3. When comparing the food labels of real versus
artificial dairy food products, it is crucial to look for the
REAL seal.
Examples of real versus artificial are the
following: half-and-half coffee cream versus
nondairy creamer, whipped cream versus whipped
toppings, cheese versus vegetable cheeses, and
butter versus margarine.
Review
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What are the steps involved in processing
milk? What are the types of milk? How do
you grade and classify milk?

How do you evaluate milk samples for
flavor and odors? How do you critique
milker head units for defects?

What are the steps in the cheese-making
process? What are the four groups of
cheese?
Review

How do you identify samples of cheese?

What are the steps of the yogurt-, sourcream-, and cottage-cheese-making
processes?

What are the steps in the butter-making
process? What are the types of butter?
Review
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What are the marketing options for dairy
products?
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What is the difference between real and
artificial dairy foods?