Ultra-high-temperature Processing

Ultra-high-temperature Processing

Ultra-high temperature processing, (less often) ultra-heat treatment (both abbreviated UHT), or ultra-pasteurization is the sterilization of food by heating it for an extremely short period, around 1–2 seconds, at a temperature exceeding 135°C (275°F), which is the temperature required to kill spores in milk. The most common UHT product is milk, but the process is also used for fruit juices, cream, soy milk, yogurt, wine, soups, honey, and stews. UHT milk was invented in the 1960s, and became generally available for consumption in the 1970s.

High heat during the UHT process can cause Maillard browning and change the taste and smell of dairy products.

UHT milk has a typical shelf life of six to nine months, until opened. It can be contrasted with HTST pasteurization (high temperature/short time), in which the milk is heated to 72°C (161.6°F) for at least 15 seconds.