UHT stands for Ultra Heat Treatment. UHT milk is not irradiated or treated with UV light. It is subjected to a very high heat treatment (~140 degrees C for 2 seconds; normal pasteurisation is to 72 degrees for 15 seconds). UHT is also underaken within extremely sterile conditions. After the flash heating the milk is packed in a sterile atmosphere with nitrogen flushed inside the package. In the absense of oxygen, and with virtually all bacteria killed by the heat treatment anyway, nothing can grow.
UHT undoubtedly affects the flavour of the liquid getting zapped, and usually the nutritional content to a much lesser degree.
Generally the shelf life for liquids subjected to UHT is about one year. UHT milk is very common in Europe and Brazil. The United States market has been extremely resistant, though. Product presentation is a key stumbling block, as antiseptic cartons are still unusual in US supermarkets and viewed with suspician by consumers there.
UHT undoubtedly affects the flavour of the liquid getting zapped, and usually the nutritional content to a much lesser degree.
Generally the shelf life for liquids subjected to UHT is about one year. UHT milk is very common in Europe and Brazil. The United States market has been extremely resistant, though. Product presentation is a key stumbling block, as antiseptic cartons are still unusual in US supermarkets and viewed with suspician by consumers there.