milk is derived from farm animals that have mammary glands such as cow, sheep and goats. Milk derived from goats has been graded as the richest and the best milk than that of cows or sheep. The method by which milk is secreted into the mammary glands of farm animal is called lactogenesis. The first milk produced immediately after parturition is called colostrum. It contains antibodies against diseases to which the mother has been exposed. It is rich proteins and vitamins.
METHODS OF MILK EXTRACTION FROM FARM ANIMAL
The two methods include :
- Hand milking method: This involves the use of two hands by the farmer to milk the animals. Very little quantity of milk is extracted. Untrimmed finger nails can cause injury to the mammary gland. This can cause infection.
Machine milking method : It is used for commercial purposes. Produce in large quantity and it is more hygienic for human consumption.
PRESERVATION OF MILK
Milk can be preserved by two major ways. These are pasteurization and sterilisation. - Pasteurization : pasteurization is the process by which the milk substance collected from farm animals with the aid of milking machine is made fit for human consumption. It simple involves the heating and cooling of the milk below the boiling point of water.
- Sterilisation : This is another way of preserving milk. It involves the heating and cooling of the milk at a temperature above the boiling point of water. By this method the germs or pathogens that may be present in the milk substance are destroyed.
ECONOMIC IMPORTANCE OF MILK
I. Milk is a source of protein in food
ii. It can be used in raising foster calves, lamb or children.
iii. It is used in the preparation of baby food
iv. It supplies minerals to livestock
v. It is used as extender in artificial insemination practices.
vi. It is used in the preparation of diary products such as butter, cheese, yoghurt etc.