Pasteurization is a process of food preservation that applies heat to eliminate pathogens and extend shelf life. In the dairy industry, pasteurization is used to heat every particle of milk or milk product to a specific temperature and hold it continuously at or above that temperature for a certain time to destroy pathogens. The process is named after the French microbiologist Louis Pasteur, who demonstrated in the 1860s that thermal processing would deactivate unwanted microorganisms in wine. The process is intended to destroy or deactivate microorganisms and enzymes that contribute to food spoilage or risk of disease, including vegetative bacteria, but most bacterial spores survive the process.
There are different types of pasteurization, including vat pasteurization, high-temperature short-time pasteurization (HTST), higher-heat shorter time (HHST), and ultra-pasteurization (UP) . The temperature and time required for each type of pasteurization are different, and they are determined based on the type of food and the pathogens that need to be eliminated. For example, in the dairy industry, milk is pasteurized at a temperature of 63°C (145°F) for 30 minutes in vat pasteurization, or at a temperature of 72°C (161°F) for 15 seconds in HTST pasteurization.
The pasteurization process is intended to destroy or deactivate microorganisms and enzymes that contribute to food spoilage or risk of disease, including vegetative bacteria, but most bacterial spores survive the process. By law, all milk sold to the public must be pasteurized and packaged in a licensed dairy plant. Raw milk can contain pathogens such as Campylobacter, E. coli O157:H7, Salmonella, Listeria, and other bacteria, which can cause disease when consumed. Therefore, pasteurization is practiced widely to enhance food preservation and promote food safety.
