What Is Ultra Pasteurized Milk?

Ultra-high temperature, or UHT, milk is ultra-pasteurized milk that comes in sterilized containers.

It’s real milk, just like the kind you buy chilled in the dairy aisle, but its special pasteurization and packaging process gives it a shelf life of several months.

Milk Ultra-Pasteurization Process

While most milk goes through a standard pasteurization process, UHT milk goes through ultra-pasteurization, which safely heats the milk to a higher-than-usual temperature. This, like regular pasteurization, kills bacteria in the milk that may be harmful or cause the milk to spoil, producing milk with a longer life. It’s then packaged in sterilized containers, also known as aseptic packaging, which helps keep the milk fresher longer.

UHT milk can sit out unrefrigerated for about three months, and this can vary by brand. Once the container is opened, the milk should be refrigerated and has the same shelf life as other milk (seven to ten days).