Cheese is a dairy product made by coagulating the protein casein in milk. It comprises proteins, fats, vitamins, minerals and water. The main steps in cheese production are pasteurization, adding starter cultures and rennet, coagulation, cutting the curd, draining whey, salting, shaping, and ripening. Ripening involves biochemical processes like glycolysis, lipolysis and proteolysis that break down proteins, lipids and carbohydrates to produce flavor compounds. Cheese can benefit bone and dental health but high intake may increase risk of cardiovascular and kidney diseases.

3. CHEESE:
• Word ‘cheese’ – Latin “casues”, meaning ‘to ferment/become sour’.
• Cheese is completely a milk product.
• Cheese is a dairy product derived from milk that is produced in a wide
range of flavors, textures, and forms by coagulation of the milk protein
casein.

4. Composition of cheese:
It comprises proteins and fat from milk, usually the milk of cows,
buffalo, goats, or sheep.
COMPOSITION:
Protein 27%
Fats 33%
Carbohydrate 0%
Vitamins (A & B) 1%
Minerals ( Calcium) 4%
water 35%

5. Classification of cheese:
• On basis of moisture percentage:

6. On basis of fat percentage:

7. Main Characteristics of Cheese:
❖ Purely milk product.
❖Widely used all over the world as food product .
❖Purely a product of microbial fermentation.
❖ Flavor and aroma changes depending upon the microorganism
being used.
❖ Before long, people learned that curds can
be aged for over weeks and months and then
pressed together to form large
cakes of cheese.

8. Principle of Cheese Production:
• Cheese – by coagulating milk (separating curd and whey)
• Both raw milk and pasteurized milk can be used for cheese making.
• Needs more rennet (up to twice) for homogenized milk than the raw
milk.
• This milk produces a curd that is smoother
and less firm than that of raw milk, so most
people add calcium chloride to the cheese

9. CHEESE MANUFACTURE
The manufacture of most cheeses involves the following
PASTEURIZATION:
It Kills nearly all microorganisms including pathogens that
cause diseases and other undesirable organisms such as
yeasts and coliforms (may alter the characteristics by
producing CO2 and undesirable proteolysis)

10. Pasteurization:

11. Cont..
❑ Regular HTST pasteurization at 72-73°C for
15-20 seconds is commonly applied.
❑ Spore forming bacteria Clostridium tyrobutyricum can survive
pasteurization and produces butyric acid and large volumes of
hydrogen gas by fermenting lactic acid, which will destroy the
structure of cheese.
❑ Chemical inhibitors such as NaNO3 or H2O2 can be used but in
several countries, it has been banned and mechanical modes have
been preferred.

12. Bactofugation:
• Process in which a specially designed centrifuge-
bactofuge is been used to separate the bacteria and
spores that present in milk.
• Efficient way of reducing the number of spores in
milk since their specific gravity is lesser than that of
milk.
• Normally separate milk into a fraction which is more
or less free from bacteria and a concentrate which
contains both spores and bacteria.

13. Typically 60-63 °C is the
temperature applied in
Bactofugation
(it was not 630)

14. Microfiltration:
• A membrane filter with a pore size of approximately 0.2 micron can
filter bacteria from a water solution
• Most of the fat globules and some of the proteins are as large as, or
larger than, the bacteria.
• This results in the filter fouling very quickly when membranes of such
a small pore size are chosen.
• In practice, membranes of a pore size of 0.8 to 1.4 micron are chosen
to lower the concentration of protein.

15. Cont.…
• In addition, the protein forms a dynamic membrane that
• contributes to the retention of micro-organisms.
• Provides an indirect sterilization
• Due to the high bacteria-reducing efficiency,
microfiltration allows production of hard and semi-hard
cheese without any need for chemicals to inhibit growth
of Clostridia spores

16. Additives in cheese milk:
 The essential additives in the cheese making process are
the starter culture and the rennet
 Under certain conditions it may also be necessary to
supply other components such as calcium chloride
(CaCl2) and saltpetre (KNO3 or NaNO3)
 An enzyme, lysozyme, has also been introduced as a
substitute for saltpetre as an inhibitor of Clostridia
organisms

17. Starter Cultures:
Two principal types of culture are used in cheese making:
 Mesophilic cultures with a temperature optimum between
20 and 40°C
 Thermophilic cultures which develop at up to 45°C.
 The most frequently used cultures are mixed strain cultures, in which
two or more strains of both mesophilic and thermophilic bacteria exist
in symbiosis
 These cultures not only produce lactic acid but also aroma
components and CO2.
 Carbon dioxide is essential for creating the eyes in round- eyed and
granular types of cheese.

18. Characteristics of starter culture:
 Three characteristics of starter cultures are of primary importance in
cheese making
1. ability to produce lactic acid
2. ability to break down the protein
3. ability to produce carbon dioxide (CO2).

19. Rennet:
 All cheese manufacture depends upon formation of curd by the
action of rennet or similar enzymes except in cottage cheeses.
 Coagulation of casein is the fundamental process in cheese
making.
 It is generally done with rennet, but other proteolytic enzymes can
also be used.
 The active principle in rennet is
• an enzyme called chymosin, and
• coagulation takes place shortly
• after the rennet is added to the milk.

20. Acid coagulation:
 Any soft cheeses are produced without use of
rennet, by coagulating milk with acid, such as
citric acid or vinegar, or the lactic acid
produced by soured milk.
 Cream cheese, paneer, and rubing are
traditionally made this way
 The acidification can also come from
bacterial fermentation such as in
cultured milk
Rubing cheese
(made by goat milk)

21. Cheese making:
A: vat during stirring
B: vat during cutting
C: vat during whey drainage
D: vat during pressing

22. Disturbances in culture:
 Slow rate of production of lactic acid or failure to produce lactic
acid.
 Antibiotics used to cure udder diseases.
 Bacteriophages, thermo-tolerant viruses found in the air and
soil.
 Detergents and sterilizing agents
ued in the dairy.

23. Acidification:
• Important for the proper release of curd from whey, and to control the
growth of undesirable bacteria.
• Achieved by the addition of lactic acid bacteria that convert lactose to
lactic acid.
• Such, carefully selected culture of lactic acid
producing bacteria is called “starter”,
without which cheese cannot be made.

24. Cont..
• The starter will be added to the homogenized milk for culturing in
large volumes and the temperature will be set to 220C, ideal for the
growth of starter.

25. Fermentation:
• Fermentation continues for about 6 to 16 hours.
• Amount of starter varies with the variety of cheese to
produce.
• The amount of lactic acid produced and the moisture in the
finished cheese regulate and control the biochemical
activities that takes place during the maturation/ripening of
the cheese.

28. Setting of coagulated milk:
• The milk has to set for about 30 minutes after the rennet has been
added.
• The milk coagulum is cut into cubes with special tools
• The size of the cubes differs depending on the kind of cheese being
made.
• Rennet- partial proteolysis of casein by cleavage at the Phe105-
Met106 .
• A rennet coagulum consists of a continuous matrix of strands of
casein micelles, which incorporate fat globules, water, minerals and
lactose and in which microorganisms are entrapped

30. Syneresis:
• Syneresis, or shrinking, of the coagulum is largely the result of
continuing rennet action.
• It causes loss of whey, and is accelerated by cutting, stirring, cooking,
salting or pressing the curd, as well as the increasing amount of acid
produced by the starter, and gradually increases during cheese
making.
• As a result, the cheese curd contracts and moisture is continuously
expelled during the cooking stages.

32. Salting:
• Salt is added to cheese as a preservative and because it
affects the texture and flavour of the final cheese by
controlling microbial growth and enzyme activity.
• The salt can be added either directly to the curd after the
whey is run off and before moulding or pressing into shape,
• Also can immerse the shaped cheese block in a salt, brine for
several days following manufacture.

33. Cont..
• Addition of salt to the cut curd draws more whey from the cheese
curd and some of the salt diffuses into the curd.
• The pH of the curd, the contact time and the salt particle size and
structure are all important in determining how much salt is absorbed
by the curd.

34. Curd Manipulation:
• Heat treatment:
• It also alters the composition and texture of the
cheese by increasing the syneresis without
increasing the acidity.
• Stretching the curd:
• Stretching the curd is an important operation for
several kinds of cheese, in particular the pasta filata
style, Mozzarella being the best known.
• Large scale production means that special machines
are used for stretching.

35. Cheddaring:
• Cheddaring is a mild form of stretching in which the
cheese curd is piled up and held warm so that water
flows under the force of gravity.
• The pH of the curd falls during this process and whey
continues to exude.
• Again, in large scale manufacture, this is done in large
• machines

37. Washing:
• Washing the curd either in the cheese vat or after de-wheying helps
remove more lactose which changes the pH of the cheese.
• It also reduces syneresis and is important in the manufacture of
cheeses such as Colby, Gouda and Egmont.

38. Moulding:
oThe formation of the final cheese shape into
• spheres,
• flattened spheres,
• discs,
• cylinders
• rectangular blocks.
oSome cheeses are pressed in moulds
(nowadays made of plastic or stainless steel)
for a short time

39. Maturation or ripening:
• Cheese ripening is basically about the breakdown
of proteins, lipids and carbohydrates (acids and
sugars) which releases flavour compounds and
modifies cheese texture.
• Ripening varies from nil for fresh cheese to 5 years
for some hard ripened cheese.
• Like a good wine, a good aged cheese should get
better and better with age.

40. Cont..
• Ripening processes are broadly classified as interior and
surface ripened.
• Cheese which depend mainly on interior ripening (most hard
ripened cheese such as Cheddar and Italian types) may be
ripened with rind formation or may be film wrapped before
curing.

41. The ripening of cheese involves three
major biochemical events.
1) Glycolysis:
Lactose is metabolized to lactic acid, which may then be catabolised
(broken down into smaller molecules) to form acetic and propionic
acids, carbon dioxide, esters and alcohol by the enzymes of the
microorganisms in the milk, including the added starter.
2) Lipolysis:
The lipids are broken down to form free fatty acids, that may then be
catabolised to form ketones, lactones and esters by natural milk
enzymes and those that are added to create the flavour in particular
cheese varieties, e.g. Romano, Blue Vein and Feta cheese.

42. 3) Proteolysis:
• Proteins (caseins) are gradually broken down to form peptides
and amino acids by the enzymes of the coagulant, the natural
milk enzymes and the enzymes of the starter bacteria and other
added microorganisms.
• The rind formation on he cheese depends on the mold being
added during ripening.
• Further proteolysis produces amino acids and the further
biochemical glycolysis and hydrolysis result in the formation of
amines, aldehydes, alcohols and sulphur compounds that add to
the flavour of the cheese.

43. Ripening of Cheese:

44. Packaging:
• Many cheeses are made and matured in large blocks (e.g. 20 kg) and
they are exported as such.
• When they are to be sold in supermarkets, they are usually cut into
appropriate size blocks and either shrink wrapped in an atmosphere of
carbon dioxide, which dissolves into the body of the cheese.
• The subsequent anaerobic environment prevents mold growth on the
cheese surface.
• Many cheeses, such as the Brie and Camembert,
are ready for sale at maturation and are packaged
in special aerating wrapping and in porous boxes.

45. Factors affecting Flavour And Texture:

46. Advantages of Cheese:
Dental Care:
• High Calcium
• Low lactose
• Raise pH of plaque offers protection against dental cavities.
Bone Health:
• Enriched in vitamin B, A, D
• Also contains calcium, magnesium, zinc
• Strengthen bones and cartilage
• Healthy for children and women

47. Cont..
Controlling Hypertension:
• Low fat cheeses such as Cottage, Feta, Ricotta are good for
hypertension patients.
Reduced Risk of Osteoporosis:
• In post menopausal women
• As cheese is enriched in vitamins, calcium and protein

48. Cont..
Omega 3 fatty acids:
• Found in cheeses made from cow milk
• Healthy for cardiovascular system and brain
• Enhance blood formation
• Strengthens liver
• Facilitate absorptions of nutrients

49. Disadvantages of Cheese:
• Cardiovascular problems:
• Cheese contains large amount of saturated fat
• High intake of saturated fats increase Cholesterol
• Results in increase risk of cardiovascular diseases, obesity, diabetes
Allergies, intolerances, sensitivities:
• Persons sensitive to casein protein develops allergies
• Fresh cheeses like mozzarella triggers reaction in persons with lactose
intolerance

50. Cont..
Kidney Disorders:
• Phosphorus in high quantities
• Harmful for persons having kidney diseases
Prostate cancer:
• High calcium causes prostate cancer
Neonatal infection and death:
• Cheese promotes growth of Listeria bacteria
• L.monocytogenes cause serious infections in infants and pregnant
woman

51. Uses of cheese:
❑ Healthy snack.
❑ Sandwiches
❑ Salads
❑ Part of main dish, pizza, lasagna
❑ Cheese sauce
❑ Garnishing, soup, spaghetti
❑ Final course.