High pressure thermal processing (HPTP) is the combination of high pressure processing (HPP) and thermal treatment. This technology takes advantage of the adiabatic heating and cooling promoted by pressure increase and decrease. That is to say, the heat generated due to compression allows fast and uniform heating of foods to elevated temperatures while decompression at the end of the process results in fast cooling.

This technology allows the sterilization of low-acid foods due to an enhanced microbial lethal effect promoted by the combination of pressure and heat. This combination allows the inactivation of spores that are unaffected by pressure alone. Being that this is a recent development, emerging applications are being validated among which the most promising seem to be baby food and RTE meals.

Compared to conventional thermal methods (e.g. retort), HPTP enables sterilization at lower temperatures and/or shorter times. Traditional thermal technologies expose foods to long heating times, due to heating thermal gradients, and long cooling times. HPTP allows the production of foods with higher quality retention due to faster and homogeneous heating and cooling phases. This results in an overall reduction in thermal load and heat-induced quality degradation. Thus, products have a better overall quality, with a reduced impact on nutritional and sensorial characteristics, as well as reduced formation of food processing contaminants related to carcinogenic activity, such as furans, acrylamides, and hydroxyl-methyl furfural.

HPTP is an ‘’In-pack’’ process, meaning that the products need to be packaged when processed, usually in their final package. Packaging materials must be flexible (to withstand compression), elastic (to recover their original shape after decompression), heat resistant (to withstand the heat applied during processing), and waterproof (as they will be submerged in water). These considerations make plastic polymers the most versatile option.

Yes, it can, with multiple beneficial results. HPTP can eliminate pathogens and spoilage microorganisms, as well as inactivate enzymatic activity resulting in increased safety and shelf-life.

It is possible to inactivate spore-forming microorganisms with HPTP, as it allows to achieve sterilization temperatures (121 °C/250 °F). There is enough scientific evidence that HPTP can inactivate Clostridium botulinum spores in different food matrixes.

Certain processing conditions used in HPTP allow to eliminate spores and inactivate enzymatic activity. Thus, it is possible to produce shelf-stable products, according to the food composition and conditions applied.