Pasteurization and Sterilization Definitions
What is Pasteurization
Pasteurization, is a process for killing bacteria that cannot withstand high temperatures in food products, thus extending the shelf life of the product. The killing curve of the bacteria is proportional to the acidity of the product and the heat applied. According to their nutritional value, the products gain durability from 1 week to 1 year.
What is Sterilization
Sterilization, is likewise performed to kill heat-resistant bacterial spores. The products are heated to temperatures of 120 ° C or 140 ° C (UHT), thus eliminating bacteria and spores. During sterilization, bacteria cannot survive. Therefore, the shelf life of sterilized products is longer than pasteurized products.
Differences of Pasteurization and Sterilization
- The disadvantage of sterilization is that it negatively affects the quality of some products. (For example, some vitamins may be lost during the procedure.)
- Heat treatments applied at temperatures below 100 °C are called pasteurization, and heat treatments above 100 °C are called sterilization. The aim of both processes is to neutralize microorganisms that cause spoilage and food poisoning, thus extending shelf life of products.
- Generally high-acid products with a pH below 4.6 (eg. fruits and fruit-based products) are pasteurized according to the target microorganism causing the degradation, while low-acid foods with a pH above 4.6 (eg. vegetables) are sterilized.
- Note: Milk is a food product that can be pasteurized and sterilized according to its targeted shelf life.(3-5 days for pasteurization, 4-6 months for sterilization)