High pressure processing is a tool which more and more is reaching industrial relevance in food processing since there are now technical systems available which allow the treatment of considerable quantities (more than 2 tons per hour) at pressures up to 800 MPa. There is a long tradition of using high pressure treatment for sterilzation or pasteurization of foods even if it was limited to scientific investigation or only small scale processing.
The main reason for its application is the lethal effect of high pressure on microorganisms. The metabolism of many living entities is adopted to atmospheric pressure at earth´s surface and an increase can disturb vital metabolic reactions or the reproduction. However, it is also known that deep sea is the habitat of a variety of organisms which obviously can withstand hydrostatic pressures up to 110 MPa. Some bacteria even survive in the vicinity of submarine hydrothermal vents where they are simultaneously exposed to elevated pressures and temperatures up to 120C. Since proteins are involved in most vital functions in living organisms, the survival of those extremophilic bacteria must be due to highly efficient stabilization mechanisms such as van der Waals contacts, hydrophobic effects, intramolecular hydrogen bonding or disulphide bridges. To chose proper conditions which can eliminate significant amounts of microbes and which are technically feasible and economically efficient in the same way is the goal of food process engineering.
An overview will be given covering the current practice of industrial high pressure technology. Related to food processing, the technical requirements for a broader application will be discussed and future research needs will be identified.