FOOD BIOTECHNOLOGY

1. PRODUCTION OF CHEESE
SUBMITTED TO- Dr. R.S. SINGH
SUBMITTED BY- NEHA SINGLA
M.Sc.(Hon’s) Biotechnology
ROLL NO.- 18011001

2. Contents-
• INTRODUCTION
• HISTORY
• TYPES OF CHEESE
• STEPS INVOLVED IN CHEESE PROODUCTION
• PROCESS DETAILS
• CHEDDAR CHEESE
• MOZZARELLA CHEESE
• COTTAGE CHEESE
• DEFECTS

3. INTRODUCTION-
• Cheese is a dairy product that is obtained from curdled milk.
• Whey is first removed from the curd and the curd is ripened in the
presence of special microflora ( e.g. Lactococcus lactis, Penicillium
roquefortii, Streptococcus thermophilus)
• As per PFA Rules (1976), cheese means the product obtained by draining
after coagulation of milk with a harmless milk coagulating agent, under
the influence of harmless bacterial cultures.

4. HISTORY-
• Process of cheese making was discovered accidentally by storing milk in a
container made from the stomach of an animal.
• 1870:- Commercial rennet preparation was put on the market.
• About 1900:- use of titrable acidity.
:- introduction of pure cultures of Lactic streptococci as starters.
:-pasteurization of cheese milk.
:-refrigeration of cheese.
:- processed cheese making.
• Recent years:- mechanization of process
:- new methods of packing.

5. • Over 400 different varieties of cheese have been recognized
throughout the world. These differ in :
1. Flavor
2. Texture
3. Appearance
• This is attributed to differences in the milk source, starter cultures,
ripening conditions, and chemical composition.

6. Primary steps involved in the
processing/production of cheese-
i. The coagulation of the casein proteins
ii. Separation of the curds from the whey
iii. Ripening of the curd

8. PROCESS DETAILS-
Receiving milk:-Physical,
chemical & biological
examination of milk.
Filtration/clarification:-Milk is
pre-heated at 35-40°C to allow
the unwanted extraneous
matter to settle down, to
improve the aesthetic quality of
the cheese made.
Standardization :-Casein/fat
ratio 0.68-0.70(for cheddar
cheese)
Pasteurization :-Holder :-63°C
for 30 min, HTST:- 71°C for 15
sec.

9. Bactofugation
(Bacterial Removal):
• The bactofuge is a high
speed centrifuge that
operates at a force of
9,80,000 kPa and 54° C.
• Removes 80 – 90
%bacteria.
• Removes 95 % of the
spores
Thermization:
• Thermization is a sub-
pasteurization heat
treatment in which
the milk is heated to
63– 65 C followed by
cooling to 4–8 C for
storage.
Ultra filtration:
• Milk for certain types
of soft cheese like Feta,
Quarg, Camembert,
Havarti.
• Done at pH 5.9 – 6.0 in
to dissociate the
calcium and phosphate
that cause bitterness.
Homogenization:
• It disrupts the
protective fat globule
membrane and the
exposed fat is subject
to rapid deterioration
by lipase unless
immediately
pasteurized.

10. Addition of calcium
chloride:- CaCl2
added
0.01-0.03 % to milk
(cheddar) and 1 ml
saturated solution per
100 litres of
milk(cottage) for the
formation of firm curd
Addition of starter:-
starter use are
Streptococcus lactis or
Streptococcus cremoris.
Added 0.5-1% of the
milk at 30-31°C.
Formation of desirable
curd.
Addition of colour:-30-
200 ml. for 1000 l of
milk(cheddar), 2-4 ml
per 1000 lt.of milk
(cottage).
Renneting :- rennet
added when acidity
increases 0.02 % from
initial level at 30°C
Coagulation : After renneting
milk starts coagulating means
becomes semi-solid. The first
sign are that when a spatula is
dipped into the milk &
withdrawn shows small flakes of
curd.
CUTTING:Refers to the cutting
of the firm coagulum into cubes
of a specific size, when a clean
break is achieved.The most
desirable acidity of whey at
cutting is approx. 0.5 % (pH 4.6-
4.7).

11. After cutting acidity reaches to
0.05-0.08 % & curd is
continuously stirred. Then the
cubes are heated to 32°C .
Cooking : Heated to the max.
i.e 37-39°C @ 1°C every 4
min.(@46°C for cottage)
WASHING AND DRAINAGE OF
WHEY ( DIPPING)
Removal of whey:-After cutting the cubes are reduced to ½ of their size , the
acidity approaches a desirable consistency, stirring is stopped
SALTING
RIPENING

12. STANDARDISATION OF MILK-
• Milk is composed of a complex mixture of lipids, proteins, carbohydrates,
vitamins, and minerals.
• The casein and fat content of the milk are standardized to minimize
variations in the quality of the cheese due to seasonal effects and variation
in the milk supply.
• The casein-to-fat ratio can be adjusted by:
--- the addition of skim milk, cream, milk powder
--- the removal of fat.
--- Calcium chloride (0.1%) may also be added to improve coagulation of the
milk by rennet and further processing of the cheese.
The actual casein and fat content of the milk will vary for each cheese type
and influence the curd formation, cheese yield, fat content, and texture of
the cheese

13. PASTEURISATION-
• Before the actual cheese making begins, the milk usually undergoes
pre-treatment. This creates optimum conditions for cheese
production.
• Milk intended for types of cheese which require more than one
month for ripening need not necessarily be pasteurised. Milk
intended for unripened cheese (fresh cheese) must be pasteurised.
• Although cheese made from unpasteurised milk is considered to have
a better flavour and aroma, most producers pasteurise the milk to
maintain its quality.

14. • Pasteurisation must be sufficient to kill bacteria capable of affecting
the quality of the cheese. Regular pasteurisation at 72 – 73°C for 15 –
20 seconds is most commonly applied.
• However, spore-forming microorganisms in the spore state survive
pasteurisation and can cause serious problems during the ripening
process. One example is Clostridium tyrobutyricum, which forms
butyric acid and large volumes of hydrogen gas by fermenting lactic
acid. This gas destroys the texture of the cheese completely
(blowing).
• More intense heat treatment would reduce that particular risk, but
would also seriously impair the general cheese making properties of
the milk. Other means of reducing thermotolerant bacteria are
therefore used. Eg addition of chemicals such as nitrates.

15. COAGULATION OF MILK-
• Aggregation of the casein micelles to form a three-dimensional gel
protein network is initiated through the addition of rennet or other
proteolytic enzymes or the addition of acid.
• Fat and water molecules are also entrapped within this protein
network. Enzymes and starter bacteria also tend to associate with the
curds, and thus contribute to a number of biochemical changes that
occur during the ripening process.
• The whey, which includes water, salts, lactose, and the soluble whey
proteins, is expelled from the gel. The aggregation of the casein
micelles by either enzyme or acid treatment results in gels with
different characteristics

17. a)BY RENNET-
• In most natural, aged cheeses, coagulation of the casein proteins by the
addition of rennet is most common. This process is temperature
dependent, with no coagulation occurring below 10°C, and an increase in
coagulation rate accompanying an increase in temperature until the
optimal temperature for coagulation (40–45°C) is reached. Above 65°C, the
enzyme is inactivated .
• The aggregation of the casein micelles is influenced by enzymatic hydrolysis
of casein. Aggregation of the micelles begins when approximately 70–85%
of the casein molecules are hydrolyzed, which reduces the steric hindrance
between the micelles.
• The presence of Ca2+ ions further facilitates the aggregation of the casein
micelles through the neutralization of the negative charge on the micelle
and the formation of ionic bonds. The resulting gel has an irregular
network is highly elastic and porous

19. b)USE OF STARTER CULTURE/ACID TO
COAGULATE THE MILK
• The production of acid by lactic acid bacteria or the direct addition of
hydrochloric or lactic acid can also result in aggregation of the casein
micelles.
• The pasteurized milk is mixed at 18-50˚C in a vat with starter culture.
Selection of starter culture depends upon the type of cheese that is
to be produced.
• The production of acid by lactic acid bacteria can result in aggregation
of the casein micelles and formation of clots.
• As the pH of the milk is reduced, the casein micelles become
insoluble and begin to aggregate.

20. • The acid-coagulated gels are less cohesive and exhibit less syneresis (
expulsion of liquid from gel ) than enzyme-coagulated cheeses.
• These cheeses generally have a high moisture content and a low
mineral content. Acid coagulation is most frequently used in the
manufacture of cottage cheese and other unripened cheeses.

21. TYPE OF CHEESE STARTER CULTURE
Cheddar Lactococcus lactis subsp. cremoris
Roquefort Lactococcus lactis subsp. lactis, Penicillium roqueforti
Limburger Lactococcus lactis subsp. lactis & cremoris, Brevibacterium linens
Camembert Lactococcus lactis , Penicillium camemberti

22. CUTTING THE COAGULUM
• A knife is stuck into the clotted milk surface and then drawn slowly
upwards until proper breaking occurs. The curd may be considered
ready for cutting as soon as a glass-like splitting flaw can be observed.
Cutting gently breaks the curd up into grains with a size of 3 – 15 mm
depending on the type of cheese. The finer the cut, the lower the
moisture content in the resulting cheese.

23. SCALDING-
• Following the cutting of the coagulum, the curd and whey mixture is heated and
agitated in a process called “scalding.”
 The agitation is necessary to keep the curds suspended in the whey and to
promote drainage of whey from the curds.
The temperature during the scalding process is dependent on the type of the
cheese and ranges from 20 to 55°C. A high temperature results in greater
drainage from the cheese and a firmer cheese. The temperature also regulates
the growth of the lactic acid bacteria.
• The conversion of lactose to lactic acid by starter cultures decreases the pH of the
curd, which contributes to the loss of whey from the curd and a decrease in
moisture content.
• When the required acidity of the cheese curds is reached, the whey is drained to
recover the curds

24. WASHING AND DRAINING -
• It is done by placing the curd cubes in a draining rack with
perforations at the bottom.
• Done to make the curd firmer & hard to touch
• It also removes acid & helps produce the desired mildness in flavour.

25. SALTING-
• The salting step reduces the moisture content of the curd, inhibits the growth of
starter bacteria, and affects the flavor, preservation, texture, and rate of ripening
of the cheese.
• The final salt content of cheese ranges from 0.7% to 4%
• The salt may be incorporated through
(1)mixing with drymilled curd pieces
(2)rubbing onto the surface of the molded cheese
(3)immersing the cheese in a salt brine.
• Following the salting step, the salt diffuses into the interior of the cheese, with
the subsequent displacement of whey.
• Depending on the size of the cheese block and the composition of the cheese, it
may take from 7 days to over 4 months for the salt to equilibrate within the
cheese.

26. RIPENING-
• Fresh, green cheese has a bland flavor and a smooth, rubbery texture. During the
ripening process, the characteristic texture and flavor of the cheese develop through a
complex series of biochemical reactions.
• The finished cheese is matured at different temperatures, humidities and times to
give the required flavor, texture and body profile.
• During ripening, degradation of proteins, lactose and fat is carried out by various
ripening agents.
• Some of the ripening agents in cheese are:
1.The bacteria and enzymes in milk
2.Rennet
3.Lipases
4.Added moulds (eg. In blue cheese)
Cheese ripening is basically about the breakdown of proteins, lipids and
carbohydrates (acids and sugars) which releases flavour compounds and
modifies cheese texture

27. RIPENING PROCESSES ARE BROADLY CLASSIFIED AS INTERIOR
AND SURFACE RIPENED-
• In all soft and semi soft cheeses, ripening conditions are such that
surface growth of micro-organism is encouraged.
• Ripening in hard cheeses occur uniformly throughout the whole
cheese mass.

28. TYPES OF CHEESE-
• The classification is based on a number of factors like raw material, type of
consistency, appearance(interior and exterior), fat content, moisture
content and ripening methods.
1. Milk utilized : cow, goat or sheep milk.
2. Curd formation method : using acids, rennet extract or both.
3. Texture or water content (%) :
 Very hard : max. 34% moisture content
 Hard : max. 39% moisture content
 Semi hard : 39-50%moisture content
 Soft cheese :50-80% moisture content
 Fresh cheese : 73-87% moisture content

29. 4. Fat content :
 Double cream cheese : 60-85% fat content
 Cream cheese: 50% or less
 Whole fat cheese : 45% or less
 Fat cheese : 40% or less
 Semi fat cheese : 20% or less
 Skim cheese : max 10%
5.Mode of ripening:
 Bacteria ripened- Swiss cheese , Cheddar cheese
 Mold ripened- (species like Penicillium used)-Roquefort cheese
 Unripened- cottage cheese, mozzarella cheese
• However the most commonly used criteria are the moisture content of the
finished product and mode of ripening-

30. NAME OF THE CHEESE MOISTURE% FAT% PROTEIN %
CHEDDAR (HARD) 35 33 26
COTTAGE (UNRIPENED) 79 0.4 16.9
ROQUEFORT 40 31 21
EDAM (SEMI HARD) 43 24 26

32. • WHITE BRINED CHEESE-
These are ripened under brine forr long period in various
concentrations of NaCl solution(10-18%), the level of salt is selective
for microbiota present in these cheese.
WHEY CHEESE-
About 50% milk solids remain in the whey, including most of the
lactose and lactalbumin.
Two different methods are used to produce whey cheese-
• The whey can be concentrated and then moulded. Cheese produced
with this method possess a relatively high lactose content. Typically
they have a yellowish to brown color and possess a sweet , cooked or
caramilised flavor.

33. • PROCESSED CHEESE-
Processed cheese is a food product made from cheese and other
unfermented dairy ingredients mixed with emulsifiers. Additional
ingredients, such as vegetable oils, salt, food coloring or sugar may be
included.
Processed cheese has several technical advantages over natural cheese,
including a longer shelf life,resistance to separating when cooked and a
uniform look and physical behavior.

34. CHEDDAR CHEESE
Receiving milk
Standardizing
(fat 3.5% : SNF
8.7%)
Starter addition
(0.5-1.25%)
Addition of
rennet
Cutting Cooking
Setting
/coagulation
(30 min)
Cutting into
blocks
millingsaltingMouldingPressing
Cheese curd
blocks
Packaging Ripening Cheese

35. CHEDDAR CHEESE- Cheddaring
(before salting)
Refers to combined operations of packing, turning, piling & repiling the curd
cubes.
Packing :-curd cubes kept closely together in 2 heaps with a channel in
between. For 5- 15 min. formation of 2 long slabs of curd. These are cut with
a cheese knife in 2 blocks 15-20 cm wide.
Turning :-blocks rolled bottom side up in the vat. For 15 min, till ready for
milling & salting.
Piling & repiling :-laying one above the other-piling. Changing the position is
repiling.
Improves texture, control moisture

36. MILLING: Mechanical
operation of cutting the
blocks of cheese into
small pieces with
cheese mill.
Types of mill-Hand
driven and Power
driven

37. HOOPING
DRESSING
PRESSING
• Curd being placed in hoops or moulds in
which the cheese is pressed into its final shape.
Temperature should be 30-32°C.
• Arrangement of cheese cloth before & after
pressing to get closed even rind or surface &
to remove all wrinkles formed during pressing.
• Operation of forcing the particles of milled &
salted curd in the hoops into the smallest
possible space.
Creaming :- The amount of 20 % cream
required to give 4 % fat, the finished product
is then homogenized before mixing so as to
form thick glossy coats over the curd particles.
Packaging & storage:- Packed in waxed /
polythene –coated paper cups or in polythene
bags. It should be stored at 5-10°C .

38. MOZZARELLA CHEESE
Receiving milk
Standardizing (fat
3.5% : SNF 8.7%)
Add conc. HCl
(250ml/100 litre
of milk)
Mild heating
(25oC)
Addition of
rennet (0.5g/100
litre of milk)
Setting
/coagulation (30
min)
Cutting
Draining the
whey
Collecting cooked
curd
Dip in hot water
(80oC)
Make balls Packaging

39. COTTAGE CHEESE-
Receiving milk
Adding calcium
chloride
Adding starter
Setting
/coagulation
(30 min)
Cutting
cooking
Draining the
whey
saltingcreamingPackaging

40. DEFECTS- (COLOUR)
Defect Causes Prevention
Acid /bleached/faded Excessive acid development Optimum acid development
in cheese
Unnatural /high Excessive addition of colour Optimum addition of colour
Mottled combining cheese from 2
vat-lot
Not combining of 2 lot
cheese curd
Seamy Incorrect addition of salt,
pressing too soon
Correct addition of salt,
pressing at right time
Uneven/wavy Pressing layers of curd from
2 different lots
Not pressing of layers from 2
different lots

41. FINISH AND APPEARANCE DEFECTS-
Defect Causes Prevention
Cracked paraffin Excessive thickness of
paraffin coating
Optimum thickness of
paraffin coating
Scaly paraffin Insufficient thickness of
paraffin coating
Correct thickness of
paraffin coating
Cracked rind Incorrect cheddaring &
drying
Correct cheddaring &
drying
Rind rot Excessive acidity /
moisture
Optimum acidity &
moisture
Huffed Excessive gassy
fermentation
Avoiding gassy
fermentation

42. BODY DEFECTS-
DEFECT CAUSES PREVENTION
CRUMBLY Excessive acid development Optimum acid development
GREASY High fat content Optimum fat content
MEALY Excessive acid development Optimum acid development
WATERY Excessive moisture Optimum moisture
WEAK High fat/moisture content Optimum fat and moisture
content

43. TEXTURE DEFECTS-
DEFECT CAUSES PREVENTION
FISH EYES Contamination with yeast Avoid yeast contamination
PIN HOLES Contamination with gas producing
micro-organisms
Avoid contamination of gas
producing micro-organisms
MECHANICAL HOLES Incorrect cheddaring Correct cheddaring
SWISS HOLES Contamination with
Propionibacterium shermanii
Avoid its contamination

44. FLAVOUR DEFECTS-
• High acid/sour:-High acid development.
• Bitter:-low quality starter, low quality milk
• Mouldy:-wrong curing, insanitary conditions.

45. REFERENCES-
• http://www.dairyconsultant.co.uk/si-cheesemaking.php
• http://www.food-info.net/uk/dairy/cheese-production.htm
• https://www.uoguelph.ca/foodscience/book-page/ripening-processes-
chemical-and-physical-changes
• http://www.cheesescience.net/2007/07/introduction-to-cheese-
science_30.html
• http://www.cib.csic.es/repositorio_bd/publicacion/1773/urls_documento/
chapter_3_publicado.pdf
• R.C. Chandan Global Technologies, Inc., Minneapolis, Minnesota, USA-dairy
fermented products
• V.K.Batish, Sunita Grover, P. Pattnaik and Niyaz Ahmed – fermented milk
products