Food poisoning

This page describes the causes of food poisoning, the symptoms to look out for and how to prevent it. Food poisoning is an acute illness, which usually happens within 1 to 36 hours of eating contaminated or poisonous food. The symptoms can include vomiting, diarrhoea, abdominal pain, nausea and fever, which normally last from 1 to 7 days.

Causes of Food Poisoning

Each type of food poisoning has a characteristic incubation period (the time it takes from eating to symptoms) and main symptoms depending on the cause. The various causes of food poisoning are listed below.

Harmful bacteria (pathogens) are the most common causes of food poisoning; it usually takes a very high number of bacteria to make someone ill.

Viruses also cause cases of vomiting and diarrhoea. They do not multiply in food but a much smaller number is needed to make someone ill. Airborne infection is common and can spread easily from person to person.

Food poisoning from chemicals is rare and usually happens when someone accidentally eats or drinks poisonous chemicals that are stored in unlabelled bottles or when food is contaminated with chemicals or additives.

Metallic poisoning causes vomiting and abdominal pains and happens when food and drink has been in contact with certain metals.

Poisonous plants/animals (such as deadly nightshade, toadstools and Japanese puffer fish) are a rare form of food poisoning, particularly in commercial premises.

More Information on Food Poisoning

Click on the links below to visit the Health Protection Agency’s website for information about various types of bacteria that cause food poisoning. 

Bacillus
Brucellosis
Campylobacter 
Clostridium botulinum
Clostridium perfringens
Cryptosporidium
Dysentery
Escherichia coli O157
Factsheets for schools
Giardia
Group A streptococci
Group B streptococci 
Group C/G streptococci
Legionnaires' disease
Listeria 
Listeria monocytogenes
Norovirus
Salmonella 
Salmonella paratyphi 
Salmonella typhi 
Salmonellosis
Shigella
Staphylococcus aureus
Streptococcal infections