MEAT AND MEAT PRODUCTS - MILK AND MILK PRODUCTS

MEAT AND MEAT PRODUCTS -

The word meat indicates the edible muscle of animals, particularly of mammals and birds. There are many species of animals that supply meat for human consumption: cattle, sheep, pigs, chickens, buffaloes, goats, ducks, turkeys and ostrich. The eating quality depends on the relative proportion of connective tissue and muscles fibre in a particular cut and on the amount of marbling fat  present in the lean.

Meat is a good source of high quality protein: iron, zinc and all the B-vitamins. Pork, bacon and ham are rich in thiamine. Liver and kidney are rich in vitamin A, folic acid, iron, riboflavin and other - vitamins. Chicken, turkey, liver and kidney contain less fat than most carcase meat and energy content is lower.

Heat causes coagulation of the proteins in the muscles, so the meat becomes firm. Cooking temperature has little affect on niacin or riboflavin while thiamin, pyridoxine, folic acid are more sensitive to heat and are destroyed between 30 and 50 per cent.   Vitamin A is quite stable to heat  and is not affected by most cooking procedures.

Meat products contribute  to the nutrient content of the average household diet

The most usual methods of heat treatment are smoking and canning, both of which cause some loss of thiamin and a slight reduction in the quality of the meat proteins.

Canned beef includes corned beef, canned hash and various potted meat.

MILK AND MILK PRODUCTS

The milk of the domestic cow is an important protein source for man and children. Milk is  a water solution of proteins, lactose, minerals and vitamins (A - C - D) that carries emulsified fat globules and colloidally dispersed casein micelles consisting of proteins together with phosphate, citrate and calcium. It is used for direct consumption, for bakery products an for making cheese, butter, casein, ice-cream, lactic acid and lactose chemicals.

When the fat is removed from whole milk, we have the product skimmed or skim milk. When the casein is precipitated out by reducing the Ph to 4,6 (20° C) the residue is called whey or serum.

Much of the production of milk is used in foodstuffs made in the form of dried milk, or milk powder, derived from skim milk.

Homogenised milk is milk treated by sonic vibrations to break up the fat globules and distribute them in the liquid.

Pasteurised milk is the milk heated to about 72°C for 15 seconds to kill disease organisms.

The UHT  (ultra-high temperature) treatment of milk at a temperature of 130°C for one or two seconds gives rise to UHT or Long-life Milk, packed aseptically into special containers to protect it from light and oxygen.

Sterilised milk is prepared from homogenised milk bottled and then heated to about 140°C for 20-60 seconds.

Evaporated milk is prepared by the concentration of milk at low temperature, then sterilised in cans at 115°C for 15 minutes.

Sweetened condensed milk is prepared with a lower temperature since it contains added sucrose.

Cheese is derived from the precipitation of casein that forms a curd. The curd is held for many hours to increase acidity, so the curd acquires the right degree of firmness. Then the curd is chopped into small pieces until it is stirred and then pressed. Salt is added before pressing. The final stage of the cheese manufacture, the ripening, requires low-temperature storage for a long period.

Cottage cheese is made from skimmed milk and contains very little fat cream. Cream cheese has a high fat content.

Certain cheeses are made from milk, others from goat or sheep milk.

Butter is produced from the separated fats of milk. The cream is pasteurised and then the starter culture is added over one or to days at 15° to 21°C. This causes the development of acidity and flavour, that is ripening. Butter that has not been ripened has better keeping qualities.

Yoghurt is made from pasteurised milk to which a starter culture is added. During an incubation at about 35°C the organisms ferment the milk lactose and produce acid. So the casein coagulates and the yoghurt is produced.