Life and death of micro-organisms in food, spoilage and preservation

Growth, survival and death of micro-organisms in food 41 Spoilage 42 Using heat to kill and injure micro-organisms in food 43 Control of microbial growth 45 Factors used to control microbial growth 46 Preservation strategies 57 Summary 58 Sources of information and further reading 58 Pathogenic viruses, protozoa, parasites and some bacteria are incapable of independent growth in food, but provided they (or their toxic products) survive the food manufacturing process, they can cause food poisoning. Many food poisoning bacteria cause disease only when eaten in the large numbers that result from multiplication in food but which does not usually alter the appearance, taste or smell of the food. Spoilage of foods is the beginning of the complex natural process of decay; it is subjective and often associated with individual taste. The growth of bacteria and fungi is a major component of spoilage. Food preservation encom - passes a series of strategies to prevent spoilage and the growth of pathogens. The control of microbiological survival and growth is often identical regardless of whether considering spoilage organisms or potential pathogens. The most common processing factor used to control micro-organisms in foods is temperature.