High pressure processing (HPP) is a non-thermal technique that allows food preservation by inactivating harmful pathogens and vegetative spoilage microorganisms that cause food-borne diseases. With this system, most foods can be efficiently preserved while minimizing the impact on taste, texture and nutritional value.
HPP utilizes intense pressure (about 400–600 MPa or 58,000–87,000 psi) at a process temperature of less than 45°C. Products in flexible and water-proof packages are conveyed within plastic baskets into a vessel which gets filled with water; this, in turn, gets pressurized at 6,000 bar. Acting uniformly, isostatic pressure inactivates food-borne microorganisms and spoilage enzymes in a few minutes while leaving no evident crushing effect on the products. After the pressure treatment, the vessel is depressurized, water is drained and products in baskets are conveyed out of the vessel.
This pressure treatment can be applied to both liquid and high-moisture-content solid foods which are treated in their final packaging, thus minimizing the risk of recontamination from any other step of the production chain. By eliminating the use of additives and heat, HPP minimizes also the risk of costly recalls therefore it can rapidly enhance business growth. The longer shelf life it guarantees helps reducing food wastage in the supply chain.
While proved lethal to microorganisms, HPP does not break covalent bonds and it barely affects food chemistry. Recent studies have shown that high pressure processing is particularly effective for fruit and meat products as, after the treatment, their appearance and consistency remain unchanged for a long time.
In a world where the vast majority of consumers have shown a growing interest in healthy, minimal-processed food products that can be stored for longer periods without losing its nutritional value, high pressure processing seems to be the new frontier of food preservation that allows food processors to develop products with a superior quality, a ten times longer shelf-life (in comparison to non-treated fresh products) and – since HPP excludes preservatives – with a clean label.