What is HPP?
High pressure processing (HPP) — also called high pressure pasteurization or Pascalization, after 17th-century scientist Blaise Pascal — uses cold water and extreme hydrostatic pressure to inactivate pathogens and spoilage organisms in food, without heat or chemical additives. Because there’s no thermal step, food keeps its fresh taste, color, texture, and nutritional value.
HPP has existed conceptually since the 1800s, but commercial equipment wasn’t developed until the 1990s. Since 2000, it’s become standard practice across juice, dips, meat, seafood, and prepared food categories worldwide.
How the Process Works
HPP is applied to food that’s already sealed in its final flexible, water-resistant package — nothing is repackaged or reopened afterward, so there’s no risk of recontamination. The process runs in four stages:
- Loading — Sealed packages are loaded into the pressure vessel.
- Vessel fill — The vessel is filled with cold water, which transmits pressure evenly around every package.
- Pressurizing — Up to 87,000 psi (600 MPa) is applied for up to 15 minutes, either constant or intermittent depending on the product. This inactivates yeast, mold, and bacteria by disrupting cell walls, while leaving the food’s chemical and nutritional makeup essentially unchanged.
- Unloading — Product is removed, dried, and prepared for shipment.
Why Non-Thermal Matters
Thermal pasteurization (heating juice to 160–180°F, or milk to as high as 280°F for ultra-high pasteurization) is effective at killing bacteria, but the heat also degrades flavor, texture, color, and nutrient/protein structure. HPP achieves comparable pathogen reduction — including against Salmonella, Listeria, and E. coli — without heat, so those qualities stay intact. It also reduces or eliminates the need for chemical preservatives.