Milk and other dairy product has been a part of human nutrition for many centuries now. Dairying is one of the main livelihood of most countries like New Zealand and Australia. Cow is the main source of milk for making dairy products, a typical dairy cow weighs from 850 to 1500 pounds depending on the breed, and it can produce about 12 times her weight in milk each year. The food that is given to a cow is very important, because it affect the flavor, quality and amount of milk that it will produce. The average cow eats 2,700 pounds of hay and grass, 1,700 pounds of grains and 6,300 pounds of silage for one year and drinks 8 gallons of water everyday.

Processing of Dairy Products:

• Raw milk is brought to the dairy plant, it is then graded, weighed, and sampled. The butterfat content determines the price paid the farmer.
• Processing of raw milk starts with clarification or separation, using centrifuges. The clarification process removes impurities like blood cells from the milk that will be sold as whole milk (milk containing all of its butterfat). Separation process removes butterfat as well as impurities from milk. Skim milk is produced when all the butterfat is removed from the raw milk.
• Dairy cows are milked 2 or 3 times a day. Most dairy farms use milking machines. The fresh milk is strained through cotton to remove foreign matters, it is then cooled in the milk house and then sold in bulk form to dairy plants. Milk is shipped by truck in 10-gallon cans or in refrigerated tank trucks.

• Milk is then pasteurized to kill harmful bacteria.
• Milk with butterfat is then homogenized to prevent the butterfat from separating from the milk.

• Processed milk is then chilled in a cooler and then placed in sterile containers.
• Processed milk is then packed individually in containers, which are usually plastic bottles or paper cartons, are put on moving racks and pass under machine that will automatically fills and seals them.

Homogenization - is the process of breaking up the fat into smaller sizes so that it no longer separates from the milk.

Pasteurization - is the process of heating liquid for the purpose of destroying viruses and harmful organism. It is different from sterilization because pasteurization only aims to reduce the number of bacteria so they are unlikely to cause disease. Sterilization is not common in food processing because it can affect the flavor.

Other Dairy Products: Butter, Cream, Cottage cheese, Yogurt, Yogurt Drinks, Flavored Milk Drinks and Ice Cream