UHT Milk Technology
Shelf safe milk is what the industry calls UHT or Ultra High Temperature, meaning that the milk has been pasteurized at a higher temperature, but for a shorter time, to preserve taste and nutrition. UHT Milk is the most common product, but the process is also used for fruit juices (juice boxes), cream, soy milk, wine, soups and broth.
Pasteurization vs UHT
With pasteurization, milk is heated to 161-167 degrees Fahrenheit with a holding time of 15-20 seconds before it is cooled. Along with correct cooling, and chilled distribution, pasteurized milk has a shelf life of five to 15 days.
In UHT treatment, milk is exposed to brief, intense heating to temperatures in the range of 275-284 degrees Fahrenheit for only three seconds. Most importantly, UHT treatment is a continuous process which takes place in a closed system that prevents the product from being contaminated by airborne micro-organisms.
The UHT milk passes through heating and cooling stages in quick succession, then is immediately put into a sterile Tetra Pak shelf-safe carton. This process avoids any re-infection. The end result is a product that lasts up to six months without refrigeration or preservatives. This is known in the industry as aseptic milk packaging.