A dairy is a business enterprise established for
the harvesting or processing of animal milk –
mostly from cows or buffaloes for human
consumption.A dairy farm produces milk and a
dairy factory processes it into a variety of dairy
6. DIFFERENT TYPES OF MILK
Standardized milk: buffalo milk & skimmed milk ( fat -
4.5% & SNF is 8.5%)
Whole milk: 3.25% milk fat & 8.25% milk solids (50% of
its calories from fat)
Reduced-fat milk (2%): This milk contains 2% milk fat (35%
of its calories)
Low-fat milk (1%): 23% of its calories from fat
7. Skimmed milk/non-fat milk: 0.5% milk fat 5% of its
calories from fat. Skimmed milk has about half the
calories of whole milk.
Pasteurized : milk 63
C for 30min kill bacteria(not
Unpasteurized - raw or untreated milk
8. Dried Milk: in powdered form.
Evaporated : homogenized milk with
considerably reduced water content
Condensed milk :simply evaporated milk to which
sugar has been added to thicken and sweeten it. It is
mainly used for making desserts and sweets.
9. VARIOUS LABROTARY TEST DONE ON
MILK BEFORE PROCESSING
Test to find bacterial contamination of milk.
Based on utilization of oxygen by bacteria which
reduces dye and decolorizes it.
Faster the decolorization, more inferior is the
bacteriological quality and vice-versa.
10. Methylene Blue Reductase Test(MBRT)
Take 10ml of milk sample in a sterile test tube.
Add 1ml of MBRT dye(dye concentration 0.005%).
Close the tube with sterilized rubber stopper.
Place in stand dipped in serological water bath maintained
Note time taken for decolorization.
11. Grading Of Raw Milk Based On MBRT
As per BIS 1479 (Part 3): 1977 criterion for grading of raw milk
based on MBRT is as below
5 hours and above Very good
3 to 4 hours Good
1 to 2 hours Fair
Less than ½ hours Poor
12. DETERMINATION OF FAT IN MILK
10 ml of H2S04 into a butyrometer tube & Mix the
Add 1 ml of Amyl alcohol ,close with a lock
Shake until homogeneous
solution. Keep in a water bath for
5min at 65o C
centrifuge for 4 min. at 1100 rpm.
Remove the butyrometer tubes and place in
water bath for 5 min.at 650C.
Read the percentage of fat
13. DETERMINATION OF SNF
Take a crucible. Note the weight of
add 5 ml of milk sample and weight it.
Put the crucible in hot air oven for 3 to 4
Remove the crucible from oven and cool
in desiccators’ and weight.
Again put the crucible for ½ hour in oven.
Remove the crucible from oven and
cooled in desiccators’ and weight.
Total solids % = Weight of residue/Weight of milk
14. DETECTION OF ADDED UREA IN MILK
5 ml of milk is mixed with 5 ml of 1.6 % of
p–Dimethyl amino benzaldehyde (DMAB) is added
Distinct yellow colour observed in milk containing
The normal milk shows a slight yellow colour due to
presence of natural urea.
Clarification: removal of small particles like straw,
hair etc. from milk .
“Bactofugation”: Centrifugal separation of
microorganisms from milk:
a) Bacteria and particularly spores have higher density
b) Two-stage centrifugation can reduce spore loads up
c) Optimal temperature for clarification is 55-60ºC
Function : to prevent creaming, or the rising of fat to the
top of the container of milk.
The process of homogenization permanently emulsifies the fine
fat globules by a method that pumps milk under high pressure
[2000–2500 lb/in2 (psi)] through small mesh orifices of a
Homogenization mechanically increases the number &
reduces the size of the fat globules. The size is reduced to
1/10 of their original size.
Resulting in the milk that maintains more uniform
composition with improved body and texture, a whiter
appearance, richer flavor, & more digestible curd.
Pasteurisation is a relatively mild heat treatment, sufficient
to destroy disease- causing microorganisms and inactivate
enzymes to extend its shelf life.
It should be followed by immediate cooling of product to the
temp. sufficiently low to check the growth of microorganisms
which are resistant to temp used.
The addition of fat-soluble vitamins A and D for Low-
fat milk & non-fat milk (usually before
It is done to increase the viscosity and appearance, as
well as the nutritive value of low-fat milk, may be
added to milk.
Pasteurized milk is first concentrated in an evaporator to
approximately 50% milk solids. The resulting concentrated
milk is then sprayed into a heated chamber where the water
almost instantly evaporates, leaving fine particles of
powdered milk solids
Milk is applied as a thin film to the surface of a heated drum,
and the dried milk solids are then scraped off. However,
powdered milk made this way tends to have a cooked flavor,
due to caramelization caused by greater heat exposure.
Same as drum drying but involves freezing which retains
more amount of nutrition.
Storage in cans: Processed milk for bulk supply is also
sometimes stored in cans.
Storage in bottles: Bottles with wide necks (36 to 40 mm),
suitable for sealing with aluminium foil caps are most
commonly used for packaging
Storage in pouches: The pillow-shaped sachets of
pasteurized milk are collected in tubs after they are cut and
separated from the packaging machine.
Cheese is made from milk and it takes approximately 5 litres
of milk to produce ½ kg of cheese.
Types of cheeses
There are four main types of cheese with numerous varieties of each.
1. Hard cheese
2. Semi-hard cheese
3. Soft or Cream cheese
4. Blue-vein cheese
Cheese is a highly concentrated form of food. Fat, protein, mineral salts and vitamins are all
present. Therefore it is an excellent bodybuilding, energy-producing, protective
Butter is a natural product made from milk. Like hard and soft
margarine’s and spreads, butter contains 81 % fat, so all have
the same number of calories.
No preservatives or colourings are added although salt may
be added for extra flavour.
Butter is made simply by churning fresh cream
25. • Ghee, a type of clarified butter, is prepared by
simmering butter and removing the residue.
The texture, colour, and taste of ghee depend
on the quality of the butter and the duration
• Buttermilk was the liquid left behind after
churning butter out of cream.
It is beneficial to health as it contains probiotic
microbes also fat content of buttermilk is far
lower than milk or curd.
It is prepared by cooling boiled milk to body temperature &
adding 5-10% starter. After 6-8 hours an acidity of 0.9-1% is
formed which coagulate the casein&curd is set.
Easily digested than normal milk. Contains more vit B than
Used as marinating & souring agent in cookery.
28. ETP PROCESS
PRELIMNARY TREATMENT: The waste water is passed
through the BAR SCREEN chamber, where a FINE bar screen
is provided to remove the floating particles from waste
water. The water is collected in collection tank.
AERATION: Now collected water is aerated by BLOWING AIR
through air blower for 24 hours , after aeration water is
transferred to neutralization tank.
NEUTRALIZATION: In this pH of waste water is adjusted
between 6-7 by adding ‘ Aluminium Bisulphate ’ or lime
29. FLOCCULATION AND COAGULATON: Flocculating agent (
alum) is added to effluent to flocculate suspended material.
Alum solution is added to the continuous mixing by
Polyelectrolyte solution is added to coagulate the flock of
suspended materials in form of SLUDGE at BOTTOM OF
TANK. Effluent transferred to septic tank.
BIOLOGICAL DEGRADATION: Nutrients are added to septic
tank for growth of bacteria that degrade the organic matter
of effluent. Urea and diammonium phosphate solution is
added and aerated for 24hrs and transferred to settling
Sludge is seperated from settling tank and water is filtered
through activated carbon filter.
30. FILTRATION: Treated effluent is then passed through the activated
carbon filter to remove coloring material and we get clean water
For example :- Filter press
Used to separate the solids from the
liquid. filter press generally work in a
batch manner. The plates are clamped
together, then a pump starts feeding
the slurry in the filter press to complete
a filtering cycle and produces a batch
of solid iron sludge filtered material,
called the filter cake. The stack plate is
opened solid sludge is removed and
the stack plate is re-clamped and
filtering cycle repeated.
From this I have learned a lot about milk its constituents,
how its stored before and after the processing ,how the
milk is processed , different items made of milk and what
happens to all the waste water of the industry and how it