The bug bible

Many types of bacteria are naturally present in food while others find their way into food from contaminated water, soil, air, animals, equipment and people. While some may spoil food, the majority of bacteria usually do not cause harm to humans.

Understanding bacterial ecology in combination with recognizing many of our bad hygiene practices can give us the tools for the prevention of foodborne disease.

Only a few micro-organisms cause foodborne illness.

Remember that food safety applies to ALL foods - the important point is to treat all foods with care.

To ensure that you are practising food safety, take a look at the following information on the micro-organisms most commonly implicated in foodborne illness.

Further information on micro-organisms is available;


  • Hocking, A.D. et al. (1997). Foodborne Microorganisms of Public Health Significance. 5th ed. North Sydney. AIFST NSW Branch Food Microbiology Group.
  • Doyle, M.P. (1989). Foodborne Bacterial Pathogens. Marcel Dekker; New York.

Glossary of terms

  • Aerobic - Microorganisms requiring oxygen to grow
  • Anaerobic - Microorganisms not requiring oxygen to grow
  • Catalase - An enzyme present in some microorganisms that converts hydrogen peroxide to water and oxygen
  • Cocci - Bacteria that are sphere shaped
  • Coccobacilli - Bacteria that are short rod shaped
  • Facultative anaerobic - Microorganisms that can grow in either aerobic or anaerobic conditions
  • Flagella - A flexible tail-like structure on some microorganisms that assist them in moving
  • Gram negative - Bacteria that when Gram stained appear red
  • Gram positive - Bacteria that when Gram stained appear purple
  • Gram stain - A staining technique that differentiates between classes of bacteria
  • Indole - A substance produced by some microorganisms
  • Microaerobic - Microorganisms that require only small amounts of oxygen to grow
  • Oxidase - An enzyme present in some microorganisms that allows them to combine oxygen (oxidation)
  • Peritrichous flagella - Flagella present around the entire bacteria pH the measurement of the acidity or alkalinity of a substance
  • Psychrotrophic - Bacteria capable of growing at temperatures below 7°C
  • Rods - Bacteria that are rod-shaped
  • Serotype - Bacteria within the same species that can be distinguished on the basis of their surface antigenic properties
  • Spores - Spherical bodies produced internally by some bacteria, that are usually more resistant to heat and chemicals
  • Water activity - The amount of water available for growth of a microorganism