Food Poisoning: Definition, Causative Agents

Last updated on May 31st, 2021

Foodborne illness, also known as “foodborne disease,” or “foodborne infection,” or “food poisoning is an important public health burden worldwide. There are an estimated 250 pathogens that can cause foodborne related illnesses. Centre for Disease Control (CDC) USA has reported 31 known agents of foodborne illness and rest are called “unspecified agents”. Foodborne illness is defined as two or more cases of a similar illness resulting from the ingestion of a common food.

It can result from consuming foods contaminated with various pathogens. In most cases, bacteria are the major pathogen followed by viruses, then parasites. However, natural or manufactured chemicals and toxins from organisms can also cause foodborne illnesses. Symptoms of food poisoning include stomach upset, abdominal cramps, nausea and vomiting, diarrhea, fever, and dehydration. Symptoms may range from mild illness to severe disease.

Foodborne Intoxications vs. Foodborne Infections

Foodborne intoxications are caused by the ingestion of toxins; natural or preformed, bacterial or chemical and the incubation period ranged from minutes to hours.  Bacillus Cereus, Clostridium botulinum, Staphylococcus aureus are the common causes of Foodborne Intoxication

Live bacteria, viruses, or parasites are responsible for foodborne infections. They invade and multiply in the lining of intestine and incubation period varies from hours to days. Campylobacter jejuni, Listeria monocytogenes, and Escherichia coli 0157:H7 are the major causes of foodborne infections.

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Common pathogens causing food-borne illness are:

Bacteria

1. Bacillus cereus: Ingestion of food contaminated with Bacillus cereus or toxins produced by this organism is responsible for foodborne illness. Bacillus cereus produces enterotoxins. It causes food poisoning of two types: diarrheal type, characterized by abdominal pain and watery diarrhea; and emetic type which is manifested as profuse vomiting.
2. Campylobacter jejuni (but also C. fetus, Campylobacter coli)
3. Clostridium perfringens
4. Clostridium botulinum: Botulism is caused by a neurotoxin from Clostridium botulinum
5. E.coli 0157:H7 (Enterohemorrhagic E. coli)
6. Listeria monocytogenes
7. Salmonella Typhimurium and S. Enteritidis
8. Shigella spp: Shigellosis is also known as bacillary dysentery. Most cases are caused by Shigella sonnei. However, S. dysenteriae, S. flexneri, and S. boydii can also cause foodborne related illnesses.
9. Staphylococcus aureus: Staphylococcus aureus makes seven different toxins that are frequently responsible for food poisoning.
10. Vibrio cholerae: cholera toxin produced by Vibrio cholerae is an enterotoxin, responsible for profuse watery diarrhea (also termed as rice watery stools).
11. Yersinia enterocolitica

Parasites

1. Toxoplasma gondii: Toxoplasmosis is caused by an intracellular protozoan, Toxoplasma gondii, which can infect all species of mammals, including humans
2. Cryptosporidium
3. Cyclospora

Virus

1. Adenovirus
2. Rotavirus
3. Calciviruses  (Better known as Norwalk virus)
4. Norwalk-like virus (or Norovirus)