Food Poisoning: Definition, Causative Agents

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.

Table of Contents

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.

MNEMONICS: “Eating Contaminated Stuff Causes Very Big Smelly Vomit”

Mnemonics	Organisms	Source
Eating	E. coli O157-H7	undercooked meat, esp. hamburgers
Contaminated	Clostridium botulinum	canned foods
Stuff	Salmonella spp	poultry, meat, eggs
Causes	Clostridium perfringens	reheated meat
Very	Vibrio parahaemolyticus	seafood
Big/Bad	Bacillus cereus	reheated rice
Smelly	Staphylococcus aureus	meats, mayo, custard
Vomit	Vibrio vulnificus	Seafood

Common pathogens causing food-borne illness are:

Bacteria

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.
Campylobacter jejuni (but also C. fetus, Campylobacter coli)
Clostridium perfringens
Clostridium botulinum: Botulism is caused by a neurotoxin from Clostridium botulinum
E.coli 0157:H7 (Enterohemorrhagic E. coli)
Listeria monocytogenes
Salmonella Typhimurium and S. Enteritidis
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.
Staphylococcus aureus: Staphylococcus aureus makes seven different toxins that are frequently responsible for food poisoning.
Vibrio cholerae: cholera toxin produced by Vibrio cholerae is an enterotoxin, responsible for profuse watery diarrhea (also termed as rice watery stools).
Yersinia enterocolitica

Parasites

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

Virus

Adenovirus
Rotavirus
Calciviruses (Better known as Norwalk virus)
Norwalk-like virus (or Norovirus)

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.