HPP or High Pressure Processing is a preservation method for fruit and vegetable smoothies (among other things) that extends the expiration date even up to 30 days.

Juices are sealed and placed into a steel compartment containing a liquid, often water, and pumps are then used to create pressure, constantly or intermittently (up to 6.000 bar or 87022,642804332 psi). The application of HPP will kill many microorganisms that play a role in the deterioration of foods.