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Differentiate between the major types of foodborne diseases -- infection, intoxication, and toxin-mediated infection.

Microbiological hazards cause most foodborne diseases in the United States. The three microbiological hazards of concern are bacteria, viruses, and parasites. These microorganisms can cause one of three types of illness -- infection, intoxication, or toxin-mediated infection.


A foodborne disease is when a person eats food containing harmful microorganisms, which then grow in the intestinal tract and cause illness. Some bacteria, all viruses, and all parasites cause foodborne illness via infection. The foodborne bacteria that cause infection are: Salmonella spp., Listeria monocytogenes, Campylobacter jejuni, Vibrio parahaemolyticus, Vibrio vulnificus, and Yersinia enterocolitica. The most common viral agents that cause foodborne disease are: Hepatitis A, norovirus, and rotavirus. The most common foodborne parasites are: Trichinella spiralis, Anisakis simplex, Giaria duodenalis, Toxoplasma gondii, Cryptosporidium parvum, and Cyclospora cayetanensis.


An intoxication results when a person eats food containing toxins that cause illness. Toxins are produced by harmful microorganisms, the result of a chemical contamination, or are naturally part of a plant or seafood. Some bacteria cause an intoxication. Viruses and parasites do not cause foodborne intoxication. The foodborne bacteria that cause intoxication are: Clostridium botulinum, Staphylococcus aureus, Clostridium perfringens, and Bacillus cereus. Chemicals that can cause an intoxication include cleaning products, sanitizers, pesticides and metals (lead, copper, brass, zinc, antimony, and cadmium). Seafood toxins include ciguatera toxin, scombroid toxin, shellfish toxins, and systemic fish toxins. Plants and mushrooms can also cause an intoxication.

Toxin-mediated infection

A toxin-mediated infection is when a person eats food containing harmful bacteria. While in the intestinal tract, the bacteria produce toxins that cause illness. Some bacteria cause toxin-mediated infection. Viruses and parasites do not cause a toxin-mediated infection. The foodborne bacteria that cause toxin-mediated infection are: Shigella spp. And Shiga toxin-producing Escherichia coli.

American Public Health Association. 2000. Control of Communicable Diseases Manual. J. Chin, Editor. Washington, DC. 624 pp.