“Microbes” is a general term used to incorporate various microorganisms (organisms that we are unable to see without using a microscope. This section presents the most common foodborne pathogens which include: bacteria, viruses, moulds, yeasts, prions and parasites (some parasites, such as certain worms, can be seen without a microscope).
 

Although many bacteria, yeasts and moulds are used to create healthy and flavourful foods such as yoghurt, wine and cheese, this section will only describe those that have the potential to cause illness in humans. These are referred to as pathogenic microorganisms or pathogens. 

 

Bacteria such as, Campylobacter, Clostridium botulinum (botulism), E. coli 0157:H7, Listeria monocytogenes, Salmonella, Shigella, Staphylococcus aureus and Vibrio parahaemolyticus are commonly associated with causing foodborne illness (see Fact sheets below for additional pathogens).

Moulds, also known as fungi, are considered potential foodborne pathogens due to some species' ability to produce toxins, referred to as mycotoxins. These toxins can be harmful to humans or animals when consumed. Examples of mycotoxins include: patulin, aflatoxin and ochratoxin.

Viruses that are pathogenic to humans do not grow in food but they can be carried in food and when ingested can lead to infection. Hepatitis A and norovirus are common viruses carried by food.

Parasites are organisms that utilize a host for a portion of their lifecycle, usually for obtaining nutrients or for reproduction. There are many types of parasites and those often associated with foodborne diseases in humans are: Trichinella, Cryptosporidium, Cyclospora and Giardia.

Prions are a relatively new type of infectious agent. They are not organisms per se but are believed to be abnormally folded proteins. Prions have become known internationally with the outbreak of mad cow disease (bovine spongiform encephalopathy) in Great Britain in the late 1980s-early 1990s.