Milk pasteurization

In 1864, Louis Pasteur developed the pasteurization process while he was tasked with finding practical solutions for problems such as keeping harmful bacteria at bay in different foods. Pasteurization is a process in which certain foods (such as milk and fruit juice) are treated with mild heat, usually less than 100 °C, to eliminate pathogens and extend shelf life.

Primarily it is designed to remove pathogenic bacteria and vegetative organisms but not heat resistant spores which are not destroyed at the temperatures employed. Raw milk can carry dangerous bacteria such as Salmonella, E. coli, Listeria, Campylobacter, and others that cause foodborne illness, often called “food poisoning.”

Second, pasteurization is designed to reduce the enzymatic activity in the product. The treatment also destroys most of the microorganisms that cause spoilage and so prolongs the storage time of food.

There are four methods of milk pasteurization
*High Temperature Short Time (HTST)
*Higher Heat Shorter Time
*Ultra-High Temperature (UHT)
*Ultra-Pasteurized

In most milk processing plants, chilled raw milk is heated by passing it between heated stainless-steel plates until it reaches 71.7°C for no less than 15 seconds. Once the milk has been heated, it is then cooled very quickly to less than 3°C. The equipment which is used to heat and cool the milk is called a ‘heat exchanger’.
Milk pasteurization