🥛 Drinking milk by processing

Drinking milk by processing is a section about the kinds of milk sold in shops and how each is treated. The milk sold in shops is almost always processed. The FAO classifies it, first, by fat content — whole, standardized, semi-skimmed, low-fat and skimmed — and second, by heat treatment: pasteurized, ESL (extended shelf life), ultra-high temperature (UHT) and sterilized. Milk can also be homogenized, fortified with vitamins, lactose-free and so on.

The main purpose of heat treatment is safety. Raw milk can carry Campylobacter, E. coli, Listeria, Brucella and Salmonella; according to the CDC, pasteurization sharply reduced milk-borne illness from the early 20th century on. The stronger the heating, the longer the milk keeps, but the more its taste and some vitamins change: pasteurized milk keeps for days or weeks in the fridge, UHT and sterilized milk for months without refrigeration.

There is also gentle heating below pasteurization levels, thermization (about 57–68 °C), used as an interim step to reduce microbes before processing. Untreated raw milk is sold in a number of countries, but health authorities consider it a higher-risk product.