Food Poisoning

Food poisoning is usually caused by eating or drinking food which is contaminated by bacteria, viruses, chemicals or toxins - most food poisoning is caused by bacteria such as Salmonella or Campylobacter. The foods most commonly involved with food poisoning are meat and poultry, shellfish, rice and dairy products, and most food poisoning is related to food prepared in the home. There is usually no way of telling whether food is contaminated as it usually looks, tastes and smells normal.

What are the symptoms of food poisoning?

The symptoms vary depending on which type of food poisoning you have, but will usually include some or all of the following;

  • Vomiting (being sick) or nausea (feeling sick)
  • Diarrhoea
  • Aching muscles
  • Headache
  • Fever
  • Tiredness
  • Abdominal pain and stomach cramps

Bacterial food poisoning can take a while before it makes you ill because the bacteria have to increase in numbers inside the body before causing illness. This can take anything from 15 minutes up to three days, so the contaminated food may not be the last food you ate although it is natural to think that it is the last meal which made you ill. However, this is often not the case.

How do I catch food poisoning?

The most common ways for food poisoning to occur are;

  • Eating or drinking contaminated food, like undercooked meat, poultry and eggs.
  • Touching contaminated food, like undercooked meat, poultry and eggs and then eating or preparing some other food without washing and drying your hands.
  • From someone who is ill with food poisoning who hasn’t washed and dried their hands properly after using the toilet.
  • Handling pets and animals without washing and drying hands properly afterwards, or allowing pets on to kitchen work-surfaces.

What are the symptoms different bacteria cause?


Found in meat, poultry, eggs and egg products, this causes nausea, cramps, diarrhoea, fever and headache. Occurs from 12 to 36 hours after eating contaminated food and can last for up to one week.

Bacillus cereus

From cereals, rice, soil and dust, this causes nausea, cramps, and diarrhoea from 1 to 6 hours after eating contaminated food, and usually lasts for 24 hours.

Staphylococcus aureus

Found in meat, poultry, eggs, cream and custard products as well as on the skin of healthy humans this causes acute vomiting, nausea, cramps and diarrhoea. It typically occurs from 30 minutes to 8 hours after consuming contaminated food and the illness can last for up to one week.

Clostridium perfringens

This is a toxic organism found in the intestine of humans, animals, birds and insects, as well as being found in soil and dust and on fruit and vegetables. It causes nausea, cramps, diarrhoea, headache and fever, 6 to 72 hours after consuming contaminated food. The illness can last for up to one week.

Clostridium botulinum

Found in soil, raw fish, vegetables, canned fish and corned beef, this is an uncommon but potentially very serious cause of food poisoning. This bacteria can cause difficulties in breathing and swallowing and paralysis within 12 to 36 hours.

Listeria monocytogenes

From soft cheeses, dips, incorrectly prepared pates, unwashed fruit and vegetables. It causes flu-like symptoms and can also cause miscarriage. Can occur from 1 to 70 days (10 weeks) after eating contaminated food.

Escherichia coli ( E. coli)

Most cases of E. coli food poisoning occur after eating undercooked beef (especially mince, burgers and meatballs) or drinking unpasteurised milk. Found in human and animal faeces, sewage, and water it is a common cause of food poisoning. Most strains are harmless but some strains can cause serious illness. The incubation period of E.coli is 1-10 days.

How do I avoid food poisoning?

Cook all meat properly especially chicken and minced meats and avoid using raw or undercooked eggs (including as an ingredient in another food e.g. mayonnaise). Avoid eating or drinking unpasteurised milk and cheeses and take care not to let blood from thawing meat drip onto other foods in your fridge.

Wash and dry your hands often, and always between handling raw and cooked foods and after using the toilet. Keep your kitchen clean, especially your dishcloths and work surfaces and keep your fridge working between 10C and 50C (get a fridge thermometer if necessary).

Keep raw and cooked food separate, including using separate chopping boards for raw and cooked foods

What special care should I take if I have vomiting and/or diarrhoea?

The most important action is good personal hygiene to avoid spreading the infection to other people. Avoid contact with as many people as possible until you have been clear of symptoms for 48 hours, and drink plenty of water, even though you may not feel like it. Vomiting and diarrhoea cause your body to lose water and dehydration can be serious over a period of several days. Most adults and children over five years should stay away from work until they are feeling better. People working with food must stay off work until they have been symptom free for two days. You must tell your employer about your illness.

People working with vulnerable groups such as the young, elderly or those in poor health, should stay off work until they have been symptom free for two days. Young children should stay away from playgroups, childminders or nursery school until they have been symptom free for two days.