Recent advances in the microbiology of high pressure processing

Ultrahigh Pressure (UHP) offers interesting possibilities for food processing ranging from extraction of plant compounds, restructuring foods and rapid formation of small ice crystals. Pressures between 300 and 600 MPa can inactivate yeasts, moulds and most vegetative bacteria including most infectious food-borne pathogens. Thus, pressure is a potential alternative to heat pasteurization as pressure leaves small molecules such as many flavour compounds and vitamins intact. In general, bacterial spores can only be killed by very high pressures (>1000 MPa). Bacterial spores, however, can often be stimulated to germinate by pressures of 50-300 MPa. Germinated spores can then be killed by relatively mild heat treatments or mild pressure treatments. However, in most cases a small fraction of spores can survive this treatment. Consequently, there is still no practical application of UHP treatment as a sterilization process, but it is still an interesting area for further exploration. (C) 1998 Elsevier Science Ltd. All rights reserved.