Ultra-high-temperature processing

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A carton of French UHT milk

Ultra-high temperature processing (or UHT) is the partial sterilization of food by heating it for a short time, around 1-2 seconds, at a temperature exceeding 135°C (275°F), which is the temperature required to kill spores in milk. The high temperature also reduces the processing time, thereby reducing the spoiling of nutrients. The most common UHT product is milk, but the process is also used for fruit juices, cream, yoghurt, wine, soups, and stews. UHT milk has seen large success in Europe, where 7 out of 10 Europeans drink it regularly.Solomon. Zaichkowsky, Polegato.Consumer Behaviour: Pearson, Toronto. 2005. pg 39 Its largest manufacturer, Parmalat, had $6 billion of sales in 1999. In the North American market, consumers have been uneasy about consuming warm milk, and have been much more reluctant in buying it. To combat this, Parmalat is developing UHT milk in old-fashioned containers. Many milk products in North American foods are made using UHT milk anyway, such as McDonalds McFlurries.

UHT milk has a typical shelf life of six to nine months, until opened. However, once contaminated, UHT milk spoils much more rapidly than pasteurized milk because all the lactobacillus in milk has been killed by the high temperature heat treatment. Many people believe that UHT products are inferior in quality to less-aggressively-pasteurized alternatives, but this is disputed by the manufacturers.

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.

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