High Pressure Processing, or HPP, is a novel food technology based on the use of high pressure. It is a very simple technology based on the Pascal principle, also known as Pascalization or cold pasteurization:
A change in pressure at any point in an enclosed fluid at rest is transmitted equally to all points through the fluid.
This technique consists in putting food like in the deepest ocean (like Mariana Trench -10.971 meters under sea level). The pressure will be applied using an autoclave filled with water until reaching the pressure of 300 MPa(3000 bar) until 800 MPa (8000 bar).
The advantages of this technique are:
- The treatment will be applied evenly to the whole product
- There are no changes in taste and appearances
- No thermal damage because the process is done with cold water
- Extended shelf life
What is interesting is that this technique can be applied on a wide range of products, especially those, which are heat sensitive. This process leads to an inactivation of bacteria, yeast, mould and most part of the enzymes responsible of food deterioration.
HPP: the future of food safety and security
HPP improves the food safety and security considering that this treatment is done after the packing of the products, so no further contamination of the products will occur after this process. The packaging should be thin and flexible enough to permit the compression of the product without breaking itself.
In the last years many studies has been conducted about the applications of HPP on dairy products, especially those made of raw milk, which have a very short shelf life. HPP of fresh cheeses enhances the maturation, kills pathogenic bacteria and improves shelf life of the product importantly. Some studies have reported that the shelf life of fresh cheeses (without microbial starters) can be extended from 7 to 21 days without major changing in taste and color.
Italian researchers are studied the reduction of Listeria Monocytegenes in Gorgonzola cheese with high-pressure processing: the result is a reduction of the 99,99% of Listeria monocytogenes and no major changes in taste. In this case, no shelf life studies were made because the major problem with Gorgonzola is the possibility of contamination with L. monocytogenes.
The process results in a natural freshness, as there are no additives, no preservatives, no freezing, and no thermal treatments. With pressure treatment, harmful pathogens and bacteria will be inactivated so that products are safe whilst keeping all the nutritional value that it was intended.
In Italy, we have few producers that are using this technology to improve the quality of some dairy products, but the scenario is changing as consequence of new market requests. Alifood, as Italian food trader, is a pioneer in modern preservation technique, an essential feature to export authentic Italian food products preserving all original properties and flavors in a natural way.
Effect of high-pressure processing (HPP) on starter-free fresh cheese shelf life. Katherine Evert Arriagada, Universitat autonoma de Barcelona, Facultat de Veterinaria.
High-pressure processing of Gorgonzola cheese: influence on Listeria monocytogenes inactivation and on sensory characteristics. Carminati D, Gatti M, Bonvini B, Neviani E, Mucchetti G.Istituto Sperimentale Lattiero Caseario, Via Lombardo, 11-26900 Lodi, Italy.