pasteurizing

Pasteurization is a heat treatment used to reduce microbial load in foods and drinks, aiming to destroy pathogens while preserving quality. Named after Louis Pasteur, the process does not sterilize; some microbes may survive, and refrigeration is often required.

Historically, Pasteur developed the method in the 1860s to prevent wine spoilage; it was later adapted to milk, which dramatically reduced tuberculosis and brucellosis risks. From the dairy industry, pasteurization spread to fruit juices, beverages, sauces, and canned foods.

Common methods include low-temperature holding (LTH), also called batch or vat pasteurization, typically 63°C for 30 minutes; high-temperature short-time (HTST) pasteurization, about 72°C for 15–20 seconds; ultra-pasteurization (UP) at around 135–150°C for 1–4 seconds. Ultra-high-temperature pasteurization (UHT) uses 135–150°C for a few seconds and is used for shelf-stable products. Equipment includes heat exchangers, pasteurizers, and continuous-flow processing.

Benefits and limitations: pasteurization reduces pathogens such as Salmonella, Listeria, and Mycobacterium bovis; it does not reliably destroy spores of Bacillus and Clostridium; some nutrients and flavors may be altered; most products require refrigeration unless UHT or aseptic packaging is used.

Regulation and labeling: many countries require pasteurized dairy and shell eggs to meet safety standards; products may be labeled pasteurized or pasteurized and homogenized in dairy. Unpasteurized products carry higher illness risk and may be restricted.