Milk processing

MILK PROCESSING
AND PACKAGING
MAJED ALGHAMDI

NUTRIENTS IN MILK
Minerals
Calcium
• Builds strong bones and teeth strengthens body cells; aids
in blood clotting; regulates muscles, including the heart;
maintains normal nerve functions
Phosphorus
• Strengthens body cells; combines with calcium to make
bones and teeth; helps in the oxidation of foods

VITAMINS
Vitamin A
Aids vision and growth; helps maintain health of mucous
membranes
Vitamin B2 (riboflavin)
Aids growth; helps maintain health of skin, eyes, and tongue;
helps nerve tissues function; helps digestive tract

VITAMINS CONTINUED
Vitamin B1 (thiamin)
Assists in maintaining normal appetite, a healthy digestive
system
Niacin
Nerve function; helps release food energy for the body’s use
Vitamin D
Helps body to use calcium and phosphorus to build strong
bones and teeth.

MACRONUTRIENTS
Carbohydrate
Lactose (milk sugar)
Provides energy
Fat
Protein
Aids growth; builds muscles; repairs worn or broken tissues.
Water
Contributes to body fluids; regulates body temperature

SOURCES OF MILK
FOOD
1- Cows
2- Others:
buffalo, goat, sheep, camel

HOW MILK GETS FROM THE
COWS TO THE STORES
Those eight steps are (in order):
1. Rearing,
2. harvesting,
3. storing,
4. transportation,
5. lab testing,
6.processing,
7. packaging, and
8. selling.

PROCESSING OF MILK
To make milk: safer more appealing or healthier
• Pasteurization,
• homogenization,
• Fortifying.

PASTEURIZATION
It is named for the French scientist Louis Pasteur,
who in the 1860s
It requires temperatures of about 63° C (145° F)
maintained for 30 minutes or, alternatively, heating
to a higher temperature, 72° C (162° F), and holding
for 15 seconds (and yet higher temperatures for
shorter periods of time).

ULTRA-HIGH-TEMPERATURE
PROCESSING
Ultra-high temperature processing (UHT), or ultra-heat treatment,
sterilizes food by heating it above 135°C (275°F) - the temperature
required to kill spores in milk - for 1 to 2 seconds. UHT is most
commonly used in milk production, but the process is also used
for fruit juices, cream, soy milk, yogurt, wine, soups, honey,
and stews
Shelf life is extended to 60–90 days
Disadvantage: The heat used during the UHT process can
cause Maillard browning and change the taste and smell of dairy
products

HIGH-TEMPERATURE SHORT-TIME
(HTST) PROCESSING
An alternative process is HTST pasteurization (high
temperature/short time), in which the milk is heated to 72°C
(161.6°F) for at least 15 seconds.
It avoid the disadvantage of last method (Maillard browning) .

HOMOGENIZATION
Milk homogenization is accomplished by mixing
massive amounts of harvested milk to create a
constant, then forcing the milk at high pressure
through small holes. Yet another method of
homogenization uses
• extruders,
• hammermills,
• or colloid mills to mill (grind) solids.
Milk homogenization is an essential tool of the milk
food industry to prevent creating various levels of
flavor and fat concentration.

HOMOGENIZATION
Homogenizing valve, a method to homogenize at high pressure.

MILK FORTIFICATION
The addition of one or more vitamins, minerals, or proteins not
naturally present in a food.
The term, fortified, also applies when added nutrients include one or
more naturally present in the food.
In the United States, the Food and Nutrition Council of the American
Medical Association pronounced in 1939 the addition of no more
than 400 IU of vitamin D per quart of milk, in the interest of public
health. The marked decline in the prevalence of rickets, a vitamin D
deficiency disorder, in the USA has been partially attributed to
vitamin D fortification of milk.

MILK SEPARATION
The fat fraction separates from the skim milk when milk is
allowed to stand for 30 to 40 minutes. This is known a
`creaming'. The creaming process can be used to remove fat
from milk in a more concentrated form. A number of methods
are employed to separate cream from milk. An understanding
of the creaming process is necessary to maximize the
efficiency of the separation process.

1- GRAVITY
SEPARATION
Fat globules in milk are lighter than the plasma phase, and
hence rise to form a cream layer. The rate of rise (V) of the
individual fat globule can be estimated using Stokes' Law
which defines the rate of settling of spherical particles in a
liquid:
V = (r2 (d1 – d2)g)/9η
where r = radius of fat globules
d 1 = density of the liquid phase
d2 = density of the sphere
g = acceleration due to gravity, and
η = specific viscosity

1- GRAVITY
SEPARATION
Figure 1. Batch separation of milk by gravity: (a) Shallow pan
method, (b) deep-setting method

CENTRIFUGAL
SEPARATION
Gravity separation is slow and inefficient. Centrifugal
separation is quicker and more efficient
Involves spinning milk through a centrifuge to separate the
cream from the milk. After separation, the cream and
remaining milk are remixed to provide the desired fat content
for the different types of milk being produced.
For "whole milk," the cream is reintroduced until the fat
content reaches 3.25%. For "low fat milk," the fat content is
1%. For "skim milk" (sometimes called nonfat milk) the fat
content is .05%.

TRANSITION OF MILK PACKAGING
21
Traditional
Steel
Containers
Glass
Bottles
Tetra
Packs
High Density
Polyethylene
(HDPC)
Pouch

GLASS
• Disadvantages include its fragility, its weight and the cost
of the one-way bottles.
• Milk exposed to fluorescent light at the grocery store for
just four hours can lose nutritional value & develop an
oxidized, burnt flavor

TETRA PACK
23
 Combines attributes of paper
plastic and aluminum
Paperboard makes the package
stable and light weight
Polyethylene are added to seal
in the liquid and protect external
moisture
 A thin layer of aluminum foil
protects product from oxygen and
light

ADVANTAGES OF
TETRA PAK®
• Excellent shelf impact and billboard effect
• Frees up to 40% shelf space
• Efficient handling and transportation thanks to square
shape and light weight. 18% more packages can fit on a
pallet, compared to cans.
• Convenient – easy to open, store and recycle

MILK - HDPE (HIGH DENSITY
POLYETHYLENE) BOTTLES
25
 Used for all three milk types :
pasteurized , UHT and
sterilized
 A three layer protection
against UV rays ( White-Black-
White)
 Preserves natural taste and
smell, flexible, durable, low
cost, eco friendly and
resistance to many chemicals
Heat sealing of bottles

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