CHEESE TECHNOLOGY

Module 8. Manufacture of different varieties of cheese

Lesson 21
COTTAGE CHEESE

21.1 Definition

a) Cottage cheese is a soft, unripened cheese that is usually made from skim milk. It has a mild acid flavor. It consists of small particles or flakes of curd, which have a meaty consistency.

b) Creamed Cottage cheese is cheese which is mixed with cream so that the mixture contains not less than 4% fat. Both Cottage cheese and creamed Cottage cheese are usually salted.

21.2 Method of Manufacture

a) There are two methods of manufacture

i) Milk coagulated by acidity developed by the action of lactic starter.
ii) Coagulation accomplished by the combined actions of lactic starter and a small quantity of rennet.

b) The two types of curd may be characterized as below:

Table 21.1 Types of curd

Table 21.2 Characteristics of long set and short set rennet curd

21.2.1 Milk for cottage cheese

Fresh, sweet, clean-flavored skim milk of low bacterial count is preferable for manufacturing Cottage cheese. Skim milk is pasteurized immediately after separation. Low Temperature Long Time (LTLT) method of pasteurization is preferable as excessive heating of milk causes soft curd formation (which is easily broken during cutting and handling).

21.2.2 Starter

High quality lactic starter is used. Bulk starter culture is prepared using skim milk.

21.2.3 Rennet

Rennet, if added, is at the rate of 15 mg per 100 l milk. Rennet diluted about 40 times with potable water for uniform distribution. Calcium chloride may be added (before adding rennet), if desired, for firm curd formation. Color may be added @ 0.5-1.0 ml/100 l (before adding rennet), if desired.

The most desirable titratable acidity of whey at cutting is approximately 0.5% (optimum pH 4.6-4.7). The whey must come from interior of curd and must be clear and free from curd particles. If the acidity is too low at cutting, curd develops a rubbery consistency. Too high acidity results in shattering of curd, giving low yield. Method of cutting and size of curd cubes is same as for Cheddar cheese.

21.2.4 Cooking

Cooking begins soon after cutting and continues for 1–2 h until temperature is about 46°C or until curd becomes firm enough to remove whey. Stirring during heating kept at a minimum and is very gently done in the early stages. The temperature is increased slowly at first. The final temperature is attained in 11/2 to 2 h.

21.2.5 Removal of whey

Whey is removed when curd cubes have no soft centres and when a handful of them squeezed gently show slight elasticity. The whey is removed from curd approximately 2 h after cutting. At this time the size of curd cubes approximate two third of their original volume. The drainage of whey is done the same way as for Cheddar cheese.

21.2.6 Washing the curd

The curd is washed after all the whey has been removed. This treatment makes the curd firmer and hard to touch; it also removes acid whey from around it and aids in producing desired mildness in flavor. The wash-water is applied in at least two treatments. The first is at a temperature of about 21°C and in amounts not less than twice the volume of curd in the vat. After 15 minutes soaking of cubes, the wash-water is removed. The second (or third, if necessary) wash-water is at 15°C or lower, in amounts as above.

21.2.7 Draining

Draining should be thorough. It is best done by placing curd cubes in a draining rack with perforated bottoms, which can be wheeled into rooms under refrigeration.

21.2.8 Salting

Salting is done when free moisture is drained from the curd. Salt can be applied to the curd in the vat or it can be dissolved in the cream for creamed Cottage cheese. It is usually done in 2 applications. Coarse salt preferred. Salt is added @ 1% or curd weight of 1.5 kg/1000 kg milk. Salted or unsalted curd is held at about 2^oC till shipping.

21.2.9 Creaming

Cottage cheese is creamed immediately after draining, if the product is to be packaged at once. Holding the curd overnight in a cold room before creaming makes it more firm at creaming. Calculated amount of 20% cream is homogenized before mixing so as to form a thick glossy coating over the curd particles.

Fig. 21.1 Manufacture of cottage cheese

21.2.10 Yield

The yield of curd before creaming depends essentially upon:

i) The composition of milk

ii) The manufacturing losses

iii) The moisture content of the cheese

While the approximate yield of uncreamed Cottage cheese is 15% of milk, that of creamed Cottage cheese (with 20% fat in cream and 4% fat in finished product) is 18.3%. The yield of Cottage cheese is given by the formula:

21.2.11 Keeping quality

Both Cottage cheese and creamed Cottage cheese have short keeping quality even under refrigerated storage (5-10°C). Uncreamed Cottage cheese may be preserved for 90 days or longer by freezing or by brine storage. However, quality will deteriorate because freezing often leads to graininess and curd shattering, particularly with rennet cheese.