What is HPP (High-Pressure Processing)?
A brief, evidence-first explainer—what it is, why it’s used, and why it’s controversial in raw feeding.
High-Pressure Processing (HPP) is a non-thermal method that uses extremely high, uniform pressure to reduce microbial loads in foods—often discussed in ranges around 400–600 MPa for short hold times.[1][2] It’s typically applied after packaging, which reduces the chance of recontamination between processing and sealing.
How HPP works (simple version)
- Food is sealed in flexible packaging.
- The package is placed in a chamber filled with water.
- Pressure is applied uniformly (“isostatically”)—not like crushing, but like deep-ocean pressure from all directions.[1][3]
- That pressure disrupts cellular structures and functions in many microorganisms, lowering their ability to grow or cause disease.[1][3]
Important nuance: HPP is often described as a “kill step,” but food safety is generally about risk reduction, not “zero risk.” Real-world effectiveness depends on food matrix, pH, water activity, time, pressure, temperature, and organism type/strain.[1][6]
Why it shows up in “raw” products
Raw foods (including raw pet food) can carry pathogens. Brands that choose HPP are usually trying to add a validated intervention that reduces the odds of:
- costly recalls and supply disruptions,
- regulatory scrutiny, and
- customer harm from mishandling or cold-chain breaks.
What HPP can’t promise
No single step makes food “sterile” in the everyday sense. Risk can be reduced dramatically, but “eliminate all pathogen risk” is too strong a claim for most real-world systems.[6]