Different types of milk (Part 1)

Sterilized Milk. This is defined as milk, which has been heated to a temperature of 100°C or above for such lengths of time that it remains fit for consumption for at least 7 days at room temperatures. Usually the milk is heated to108-111°C for 25 to 30 min. Commercially sterilized milk is rarely sterile in the strict bacteriological sense. This is because the requirements for the complete sterility conflict with the consumer’s preference for normal colour and flavour in the sterilized product.

Flavoured Milk. It is milk to which some flavours have been added. When the term milk is used the product should contain a milk fat percentage of a least equal to the minimum legal requirement for market milk. But when the fat level is lower (1-2 per cent) the term ‘drink’ should be used.

Acidophilus Milk. It is fermented milk, produced by development in milk of a culture of Lactobacillus acidophilus. It is claimed that acidophilus milk has therapeutic and health promoting properties. It is also claimed that the growth of Lactobacillus acidophilus under the conditions existing in the intestinal tract will replace undesirable putrefactive fermentations with a beneficial lactic fermentation.

BUTTER

Butter may be defined as a fat concentrate, obtained by churning cream, gathering the fat into compact mass and then working it.

According to the PFA rules (1976), table creamery butter is the product obtained from cow or buffalo milk or a combination there of, or from cream or curd from cow or buffalo milk or a combination thereof with or without the addition of common salt and annatto or carotene as colouring matter. It should be free from other animal fats, wax, and mineral oils, vegetable oils and fats. No preservatives except common salt and no colouring matter except annatto and carotene may be added.

Butter must contain not less than 80 % by weight of milk fat, not more than 1.5 % by weight of curd, and not more than 3% by weight of common salt. Diacetyl may be added as a flavouring agent but if so used the total diacetyl content must not exceed 4 ppm. Calcium hydroxide, sodium carbonate, sodium polyphosphate may be added, but must not exceed the weight of butter as whole by more than 0.2 %. These are the standards prescribed for butter as per the PFA rules. Butter is very rich in fat and fat soluble vitamins A, D, E and K.

Different types of milk (Part 2)

Homogenized Milk. It is milk, which has been treated in such a manner as to insure break up of fat globules to such an extent that after 48 h of quiescent storage no visible cream separation occurs on the milk; and the fat percentage of the milk in the top 100 ml of milk in a quart bottle or proportionate volumes in containers of other sizes, does not differ by more than 10 per cent of itself from the fat percentage of the remaining milk as determined after thorough mixing.

Mineralized Milk. It is milk to which some minerals have been added.

Vitaminized or Irradiated Milk. Vitaminized milk is milk to which one or more vitamins are added. Irradiated milk is milk in which the vitamin D content has been increased by exposure to ultra violet rays. Addition of vitamins (and minerals) to milk is called fortification and such milk is called fortified milk. The vitamins and minerals may be added singly or in combination as multi-vitamin and mineral milk preparations.

Kefir. It is a self carbonated milk beverage containing 1 per cent lactic acid and 1 per cent alcohol. The fermentation is usually done by kefir grains, which contains Streptococcus lactis, Betabacterium caucasium, keir bacilli and lactose fermenting yeasts.

ICE CREAM

Ice cream is a frozen dairy product prepared by suitable blending and processing of cream and other dairy products together with sugar and flavour, with or without stabilizers or colour, and with the incorporation of air during the freezing process.

According to the PFA rules (1976), ice cream may be defined as a frozen product obtained from the cow or buffalo milk or a combination thereof or from cream and/or other milk products, with or without the addition of cane sugar, eggs, fruits, fruit juices, preserved fruits, nuts, chocolate, edible flavours and permitted food colours. It may contain permitted stabilizers and emulsifiers not exceeding 0.5 per cent by weight. The mixture must be suitably heated before freezing. The ice cream should contain not less than 10% milk fat, 3.5% protein, and 36% total solids.

Different varieties of ice creams are available in the market catering to the varied tastes of the consumers. They are plain, chocolate, fruit, nut, milk ices or milk lollies, fancy moulded, novelties and softy ice creams. An average quality ice cream should have 10% milk fat, 10-11% solids not fat, 13-15% sugar, 0.3-0.5% stabilizer and emulsifier and total solids content in the range of 35-37%. If it has to be a good quality ice cream, it should have 12% milk fat, 11% solids not fat, 15% sugar, 0.30% stabilizer and emulsifier and total solids 39%.