Ultrahigh temperature-treated milk 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.[1] The most common UHT product is milk, but the process is also used for fruit juices, cream, soy milk, yogurt, wine, soups, and stews.[1] UHT milk was invented in the 1960s, and became generally available for consumption in the 1970s.[2] High heat during the UHT process can cause Maillard browning and change the taste and smell of dairy products.[3] 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.