This is some copy from the article in Food Safety News which is quite extensive and has links to videos of HPP in practice.
“Pascalisation,” commonly known in the food industry as HPP, or high pressure processing. Has only been used on the commercial level for the past 2 decades or so, the technology has been around far longer than that.
This process doesn’t rely on heat, such as pasteurisation; or chemicals, such as preservatives; or irradiation to kill the harmful bacteria on food. And while heat and cooking are good ways to kill bacteria, they can also impair the flavor, texture, color and nutrition of the food. For the most part, the same is true of irradiation.
Under high pressure processing, already packaged products such as fresh hamburger and turkey; processed fruit such as apple sauce; oysters; fish; guacamole; and ready-to-eat meats such as sliced turkey, pastrami and beef are put inside a pressure chamber. Water is then added to the chamber before it is sealed. From there, the pressure is increased to the maximum desirable level and sustained for a set period of time. The chamber is then decompressed and drained and the packaged products are removed.
FoodWorld 