cheese

CHEESEMAKINGCHEESEMAKING

ADAMS SADIK

INTRODUCTIONINTRODUCTIONCheese is the fresh or ripened product

obtained after coagulation and whey

separation of milk, cream or partly

skimmed milk, buttermilk or a mixture of

these products.

It is not known when cheesemaking was

first discovered but the cheese of

yesterday was just curds and whey.

A curd is the solid custard-like state of

milk achieved when milk coagulate due to

acidification and addition of enzyme.

Curds

Whey

The whey is the liquid portion of milk

which develops after coagulation of the

milk protein. It contains water, milk sugar,

albuminous proteins, and minerals.

INGREDIENTS FOR INGREDIENTS FOR CHEESEMAKINGCHEESEMAKING

Milk:

The most important ingredient in cheese

is milk. The milk of many mammals can be

used but the milk of ruminants is the best.

This is because it contains high levels of

the milk protein, casein, which is required

to provide an adequate coagulum.

Starter:

There are two types which are the

mesophilic and the thermophilic cultures.

It is usually bacteria but fungi can play a

role, such as in blue cheese.

Three characteristics of starter cultures of

primary importance in cheese making are:ability to produce lactic acid in the curdability to break down the protein

ability to produce CO2 when applicable.

Coagulant:

Rennet is the usual coagulating enzyme

used. Rennet is an enzyme which acts on

protein and causes it to coagulate.

It is mostly extracted from the fourth

stomach of young ruminants. The main

enzyme contained in rennet is rennin.

Salt:

Sodium chloride is added to most

varieties of cheese to give it flavour.

The quantity and method of addition

depends on the recipe.

It may be added directly to the milk or

curd pieces, rubbed into the finished

cheese or immersed in a brine solution.

Colour:

The recipe determines if colouring matter

should be used.

Chemicals:

CaCl2 is frequently added to aid

coagulation and reduce amount of rennet

required.

Sodium or Potassium nitrate inhibits

pathogenic microbes such as the gas

forming Clostridium tyrobutyricum.

THE MANUFACTURING THE MANUFACTURING PROCEPROCESS1.Milk Treatment

Methods to reduce microbial numbers

Clarification Bactofugation Microfiltration

Heat treatment Thermisation (63-65oC shortly)Pasteurization (63oC, 30mins or 72oC, 16s) Heat treat (55-65oC for 16 seconds)

Standardization to improve the quality of the milk used.

2. Acidification

The bacteria feed on the lactose in milk

and produce lactic acid as a waste

product.

The acid is required to:

Assist coagulation

Promote syneresis

Prevent growth of pathogenic and

spoilage

bacteria.

Develop cheese texture, flavour and

colour

LAB are grouped by four criteria, namely

Principal metabolites (homo-

fermentative

and hetero-fermentative)

Optimum growth temperature

(mesophilic and thermophilic)

Starter composition

Forms of inoculation

SpeciesMajor Known

FunctionProduct

Propionibacterium shermanii

Flavour and Eye formation

Swiss cheese family

Lactobacillus bugaricusLactobacillus lactisLactobacillus helveticus

Acid and flavour

Yoghurt, Swiss, Emmental, and Italian cheeses

Lactobacillus acidophilus

Acid Acidophilus buttermilk

Streptococcus thermophilus

AcidEmmental, Cheddar, and Italian cheeses, and yogurt

Streptococcus duransStreptococcus faecalis

Acid and flavour

Soft Italian, cheddar, and some Swiss cheeses.

Leuconostoc citrovorumLeuconostoc dextranicum

FlavourCultured buttermilk,, cottage cheese, and starter cultures.

Some microbes involved in cheesemaking

Secondary Microbes

Large holes: Propioni bacterium freudenreichii subsp. Shermaniee

White moulds: Penicillium camembertii, P. caseiocolum and P. candidum

Blue/green moulds: Penicillium roqueforti, P. glaucum

Ripening adjuncts: Bacterial or yeast cultures added in addition to the regular LAB cultures

Attenuated cultures which are not intended to grow but only to contribute their enzymes.

3. Coagulation

Casein exists as micelles in milk. During

coagulation, the casein micelles stick

together. The natural tendency of

casein is to clump together they are

hydrophobic.

Two factors prevent their sticking

together in normal milk. These are: Kappa-casein on the surface of the

micelle. A negative charge on the micelles

which make them repel each other.

4. Cutting and Pressing the cheese

This step is usually accompanied with

heating the curd. Cutting the curd

allows whey to escape, while heating

increases the rate at which the curd

contracts and squeezes out the whey.

Not set for cutting

Set for cutting

COOKING THE CURDS

The curds are cooked after allowing to

sit for about 15mins with stirring to

prevent the curds from clumping

together. Larger curds are cut as they

appear but not squeezed.

The combination of heat and the

developing acidity causes syneresis with

resulting expulsion of moisture, lactose,

acid, soluble minerals and salts, and

whey proteins.

The curd is cooked until it is 34oC for soft

curd cheese or as high as 39oC for very

firm cheese.

The cooked curds are made to sit for a

while so that they sink in the remaining

whey. Floating curds after a while means

there is the possibility of having gas-

producing contaminants in the starter.

This makes separation of curds from whey

difficult.

SALTING:

Almost all cheese is salted by one of the

three methods: before pressing, surface

salting after pressing, or brine salting.

The purpose of salting is to:Promote further syneresisSlow acid developmentCheck spoilage bacteriaPromote controlled ripening and flavour

development (salty flavour)

PRESSING:

Pressing the curd in the moulds assists in

some whey removal and compacts the curd

pieces into the shape of the mould.

The temperature of the curd and the extent

of pressing are critical to the quality and the

appearance of the final cheese.

The cheese is then placed in a cheese cloth

and may be coated with a thin layer of butter

for storage and for maintenance of its shape.

5.Ripening

Cheese ripening is the breakdown of

proteins, lipids and carbohydrates

(acids and sugars) which release

flavour compounds and modifies

cheese texture. The principal ripening

agents:

Milk enzymes: Plasmin Lipoprotein

LAB cultures

Secondary cultures

Rind formation, the outer covering of

cheese, occurs during the ripening stage.

The basic function of rinds is to protect

the interior of the cheese and allow it to

ripen uniformly.

Salting plays an important role in rind

formation. Heavily salted cheeses develop

a thick, tough outer rind.

COLOURING

Goat and sheep milk are whiter than cow

milk due to the lack of carotene hence

their cheese is whiter.

Cow’s milk may be whitened by using

legal whitening agents such as Titanium

dioxide

Goat and sheep milk can also be given

colour by the addition of annatto, a

natural vegetable extract which contains

carotene.

Cheese Type

Moisture %

fat-free basis

Extra hard

< 41

Hard 49 – 56

Semi-hard

54 – 63

Semi-soft 61 – 69

Soft > 67

Cheese Type

Fat %total solids basis

Skim < 10

Low fat 10 – 25

Medium fat

25 – 45

Full fat 45 – 60

High fat > 60

CLASSIFICATION OF CLASSIFICATION OF CHEESECHEESE

On the basis of curing, cheese can be

classified as:

Cured or ripened cheese: cheese

which is to be kept for some time under

certain conditions before consumption is

possible.

Mould cured or mould ripened

cheese: the curing is achieved by mould

growth

Uncured, unripened, or fresh

cheese: this is cheese which is ready for

consumption shortly after manufacture.

Examples of cheese, the microbes involved and the category they can be placed

CHEESE MICROORGANISMS

SOFT, UNRIPENED

Cottage Lactococcus lactisLeuconostoc citrovorum

Cream Streptococcus cremoris

Neufchatel Streptococcus diacetilactis

SOFT, RIPENED1 – 5 MONTHS

Brie

Lactococcus lactis Penicillium candidiumStreptococcus cremorisPenicillium camembertiBrevibacterium linens

Camembert

Lactococcus lactis Streptococcus cremoris Penicillium candidium Penicillium camembert

Limburger Lactococcus lactis Brevibacterium linens Streptococcus cremoris

CHEESE MICROORGANISMS CHEESE

SEMISOFT, RIPENED1 – 12 MONTHS

Blue

Lactococcus lactis Penicillium roqueforti Streptococcus cremoris Penicillium glaucum

Brick Lactococcus lactis Brevibacterium linens Streptococcus cremoris

Gorgonzola


MontereyLactococcus lactisStreptococcus cremoris

MeunsterLactococcus lactis Brevibacterium linens Streptococcus cremoris

Roquefort


CHEESE MICROORGANISMS

HARD, RIPENED3 – 12 MONTHS

EdamLactococcus lactis, Streptococcus cremoris

Gruyere Lactococcus lactis Lactobacillus helveticus Streptococcus thermophilus Propionibacterium sheranii or Lactobacillus bulgaricus andPropionibacterium freudenreichii

Swiss Lactococcus lactis Lactobacillus helveticus Propionibacterium shermanii or Lactobacillus bulgaricus and Streptococcus thermophilus

VERY HARD, RIPENED12 – 16 MONTHS

Parmesan Lactococcus lactis Lactobacillus bulgaricus Streptococcus cremoris Streptococcus thermophilus

CONCLUSION

Cheese is a fermented milk product

made from the curds produced when

water is removed from milk and it

coagulates. It can be made from a

variety of milk such as cow, goat, sheep

and buffalo milk.

Lactic acid bacteria and other

microorganisms are needed to cause the

souring of the milk and to give it the

characteristic taste, texture and flavour.

REFERENCES

O’Connor C. B. (1993). Traditional Cheesemaking Manual, International Livestock Centre for Africa, Addis Ababa, Ethiopia.

http://www.foodsci.uoguelph.ca/cheese.htm, University of Guelph. A detailed description of the cheemaking processes. Visited 29/10/2008.

http://www.geocities.com/Heartland/Cottage/1288/intro/Intro.htm, Geocities. Introduction to cheesemaking. Visited 27/10/2008.

http://www.leeners.com/cheesehow2.html, Leeners. Cheesemaking instructions. Visited 27/10/2008.

http://biology.clc.uc.edu/fankhauser/Cheese/Cheese_5_gallons/CHEESE_5gal_00.htm, CLC University. A page illustrating cheesemaking. Visited 27/10/2008.

http://www.wisegeek.com/what-are-the-different-types-of-cheese.htm, WiseGEEK, What are the different types of cheese? Visited 27/10/2008.

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