20. Factors Affecting the Growth of Microorganisms in Food

  1. Rajeev Bhat2,
  2. Abd Karim Alias2 and
  3. Gopinadhan Paliyath3
  1. Siddig Hussein Hamad

Published Online: 16 JAN 2012

DOI: 10.1002/9781119962045.ch20

Progress in Food Preservation

Progress in Food Preservation

How to Cite

Hamad, S. H. (2012) Factors Affecting the Growth of Microorganisms in Food, in Progress in Food Preservation (eds R. Bhat, A. Karim Alias and G. Paliyath), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781119962045.ch20

Editor Information

  1. 2

    Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia

  2. 3

    Department of Plant Agriculture, University of Guelph, Guelph, Canada

Author Information

  1. Department of Food and Nutrition Sciences, College of Agricultural and Food Sciences, King Faisal University, Saudi Arabia

Publication History

  1. Published Online: 16 JAN 2012
  2. Published Print: 10 FEB 2012

ISBN Information

Print ISBN: 9780470655856

Online ISBN: 9781119962045

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Keywords:

  • contamination;
  • extrinsic factors;
  • freezing;
  • implicit factors;
  • intrinsic factors;
  • microorganisms;
  • processing factors

Summary

When microorganisms grow in food they cause varying degrees of change in the food's characteristics as a result of metabolic activity. Some of these changes, like those taking place during fermentation, are desirable, while others, like those resulting in food spoilage and food poisoning, are undesirable. The role of the food technologist is to encourage the desirable and prevent the undesirable changes. The most important factors that affect microbial growth in foods can be summarized in the following categories: (i) factors related to the food itself, the “intrinsic factors,” which include nutrient content, water activity, pH value, redox potential, and the presence of antimicrobial substances and mechanical barriers to microbial invasion; (ii) factors related to the environment in which the food is stored, the “extrinsic factors,” including the temperature of storage, and the composition of gases and relative humidity in the atmosphere surrounding the food; (iii) factors related to the microorganisms themselves, the “implicit factors,” including interactions between the microorganisms contaminating the food and between these microorganisms and the food, e.g., their abilities to utilize different nutrient sources, tolerate stresses, and produce promoters or inhibitors of growth of other microorganisms, etc.; (iv) processing factors, which include treatments such as heating, cooling, and drying that affect the composition of the food and also affect the types and numbers of microorganisms that remain in the food after treatment; and (v) interaction between the above-described factors can also affect the growth of microorganisms in foods in a complicated way; the combined effects may be additive or synergistic.