Chapter 4: The Microbiology of Food Preservation

All food preservation procedures are based on control of the factors influencing microbial growth and survival and many rely on a combination of inhibitory factors to achieve a food’s keeping quality and safety. Although most preservation methods were developed empirically before the role of micro-organisms was known, their current successful use on a large scale is critically dependent on understanding the application of underlying scientific principles. A few techniques, such as irradiation and high-pressure processing, were developed more recently and in these cases control of micro-organisms was a clear objective from the start of their development. All the important techniques of food preservation are described in some detail – the basis of the inhibitory effects involved, the kinetics and mechanisms of microbial inactivation, direct and indirect methods of heating and thermal process calculation, aseptic packaging, irradiation, modified atmosphere packaging (MAP), chill storage and freezing. Key chemical preservatives and their mode of action, including ‘natural’ preservative systems, and the use of compartmentalisation in emulsion systems are discussed.