Ultrahocherhitzung

Ultrahocherhitzung, often abbreviated as UHT, is a food processing method that involves heating liquid food products, most commonly milk, to a very high temperature for a short duration. This process typically involves heating the product to at least 135 degrees Celsius (275 degrees Fahrenheit) for one to two seconds. The primary goal of UHT is to kill all microorganisms, including bacteria, yeasts, and molds, as well as their spores, thus significantly extending the shelf life of the product without the need for refrigeration.

The UHT process is usually carried out using indirect heating methods, such as plate heat exchangers or scraped surface heat exchangers, where the product is heated by passing it through a system with hot water or steam. Alternatively, direct heating methods, like injecting steam directly into the product, can also be employed. After the heating phase, the product is rapidly cooled down and then filled into sterile packaging, often aseptic containers. This aseptic packaging is crucial for maintaining the product's sterility and preventing recontamination.

Products treated with UHT, such as milk, cream, and juices, can be stored at room temperature for several months, or even up to a year, before being opened. Once opened, however, they typically require refrigeration and should be consumed within a few days, similar to conventionally pasteurized products. While UHT processing effectively destroys microorganisms and enzymes that cause spoilage, it can sometimes lead to minor changes in the taste and nutritional profile compared to fresh or pasteurized products, though these changes are generally considered insignificant by most consumers.