Methods of food preservation
3. Pasteurization
This
involves heating food to a temperature high enough to kill any harmful
microorganisms, but low enough to preserve the food’s flavor and texture.
Several methods are common:
Low-Temperature Long-Time (LTLT) pasteurization, also called “batch” pasteurization or “vat” pasteurization, is commonly used in small-scale and artisanal operations, where milk is heated to 63°C for 30 min.
High-temperature short time (HTST) pasteurizationis a continuous process accomplished by
heating the product to 71.5°C and passing through a holding tube at a
rate that ensures the required holding time of 15 sec.
Low-temperature short-time (LTST) is a method that uses heat lower than the usual pasteurizing temperature and low pressure to pasteurize a fluid milk product by spraying droplets in a chamber heated below the usual pasteurization temperatures, thereby increasing the overall quality of the product.
Ultra-high-temperature (UHT) pasteurization involves heating milk or cream to 138–150 °C for 1 or 2 sec.