Food poisoning symptoms & treatments – Illnesses & conditions | NHS inform

food can become contaminated at any stage during its product, serve or cook .
For model, it can become contaminated by :

  • not cooking food thoroughly (particularly meat)
  • not correctly storing food that needs to be chilled at below 5C
  • keeping cooked food unrefrigerated for a long period
  • eating food that has been touched by someone who is ill or has been in contact with someone with diarrhoea and vomiting
  • cross-contamination (where harmful bacteria are spread between food, surfaces and equipment)

Cross-contamination can occur, for case, if you prepare natural chicken on a chopping board and do n’t wash the board before preparing food that wo n’t be cooked ( such as salad ), as the harmful bacteria can be spread from the chopping board to the salad .
It can besides occur if raw meat is stored above ready-to-eat meals and juices from the kernel dribble on to the food below.

See preventing food poisoning for information about reducing these risks

Types of infection

Food contaminant is normally caused by bacteria, but it can besides sometimes be caused by viruses or parasites. Some of the chief sources of contaminant are described below .


In the UK, campylobacter bacteria are the most common lawsuit of food poison. The bacteria are normally found on bare-assed or undercooked kernel ( peculiarly domestic fowl ), unpasteurized milk and untreated water .
The incubation period ( the time between eating contaminated food and the start of symptoms ) for food poison caused by campylobacter is normally between two and five days. The symptoms normally final less than a workweek .


salmonella bacteria are often found in bleak or undercooked kernel, bleak eggs, milk, and other dairy products .
The incubation period is normally between 12 and 72 hours. The symptoms normally final around four to seven days .


Listeria bacteria may be found in a scope of chilled, “ ready-to-eat ” foods, including pre-packed sandwiches, cooked slice meats and pâté, and soft cheeses ( such as Brie or Camembert ) .
All of these foods should be eaten by their “ use-by ” dates. This is particularly important for pregnant women, because a listeria infection ( known as listeriosis ) in pregnancy can cause pregnancy and birth complications, and can result in miscarriage .
The brooding time period can vary well, from a few days to respective weeks. The symptoms will normally pass within three days .

Escherichia coli (E. coli)

Escherichia coli, frequently known as E. coli, are bacteria found in the digestive systems of many animals, including humans. Most strains are harmless but some can cause good illness.

Most cases of E. coli food poisoning happen after eating undercooked beef ( peculiarly mince, burgers and meatballs ) or drinking unpasteurized milk .
The incubation period for food poison caused by E. coli is typically one to eight days. The symptoms normally final for a few days or weeks .


shigella bacteria can contaminate any food that has been washed in contaminate water .
Symptoms typically develop within seven days of eating contaminated food and last for astir to a week .
An contagion caused by Shigella bacteria is known as bacillar dysentery or shigellosis. See the subject on dysentery for more data about it .


The virus that most normally causes diarrhea and vomit is the norovirus. It ‘s easily spread from person to person, through contaminated food or body of water. Raw mollusk, peculiarly oysters, can besides be a generator of infection .
The brooding period typically lasts 24-48 hours and the symptoms normally pass in a copulate of days .
In young children, the rotavirus is a coarse cause of infection from contaminated food. The symptoms normally develop within a week and pass in approximately five to seven days .


In the UK, food poison caused by parasites is rare. It ‘s much more common in the train world.

parasitic infections that can be spread in contaminate food admit :

  • giardiasis – an infection caused by a parasite called Giardia intestinalis
  • cryptosporidiosis – an infection caused by a parasite called Cryptosporidium
  • ameobiasis – a type of dysentery caused by a single-cell parasite (ameoba) called Entamoeba histolytica (this is very rare in the UK)

The symptoms of food poison caused by a parasite normally develop within 10 days of eating contaminated food, although sometimes it may be weeks before you feel ailing .
If left untreated, the symptoms can end a hanker time – sometimes several weeks or even a few months .