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Food poisoning

Food poisoning and foodborne illness

Many microorganisms can cause infectious intestinal disease and because of this signs, symptoms, incubation periods and modes of transmission vary.

The most common signs of infectious intestinal disease are vomiting and/or diarrhoea, but other symptoms such as fever, stomach aches and bloody stools may also be present.

Food poisoning and foodborne illness are caused by eating contaminated (or more rarely poisonous) food or water. Most people will get better without the need for treatment. In most cases, the food that causes the illness has been contaminated by bacteria, such as salmonella, or a virus, such as the norovirus or a toxin produced by such an organism.


Public Protection investigate notifications of some infectious diseases along with colleagues at Public Health England (formerly the Health Protection Agency). The aim of any investigation is to try to identify a cause and help limit any further spread of an illness.

When a notification, or complaint, about alleged food poisoning is made we will try to contact the person with the symptoms to find out more details. It is important to remember that food poisoning symptoms can be caused by other problems or infections, eg certain viruses can be picked up directly from other people or contaminated surfaces. It is also not necessarily the last meal you had that made you ill, some infections can take more than a week to cause symptoms. 

Note: People in occupations, such as nurses, food handlers and people who work with the young or elderly must not go to work if they have food poisoning as there is a possibility that they may spread the infection. Young children will also need to be kept from playgroups or nurseries until they are clear of symptoms.​


The symptoms of food poisoning usually begin one to three days after eating contaminated food or water, but can take longer. Symptoms include:

  • feeling sick
  • vomiting
  • diarrhoea
  • stomach cramps

Further information on some organisms associated with illness. ​

Foods involved

Foods that are particularly vulnerable to contamination or which can cause problems if they are not handled, stored or cooked properly include:

  • raw meat and poultry
  • 'ready to eat' foods such as cooked sliced meats, pate, soft cheeses and pre-packed sandwiches
  • dairy products, such as eggs and milk

How common is food poisoning?

During 2010, there were almost 56,991 cases of food poisoning in England and Wales. However, the actual figure may be considerably higher than this because many people with mild symptoms do not report them.


Most people with food poisoning will get better without the need for treatment. In the meantime, you can relieve the symptoms of food poisoning by:

  • drinking plenty of fluids
  • eating easily digested food, such as toast, until you feel better
  • resting

Occasionally, food poisoning can have more serious effects on a person’s health, particularly if they are already vulnerable to the effects of an infection. For example, being older than 65 or having a condition that weakens the immune system, such as HIV or cancer, can increase a person's chances of getting an illness and developing more serious symptoms.

Signs that you may have a more serious case of food poisoning that requires medical attention include:

  • vomiting that lasts for more than two days
  • not being able to keep liquids down for more than a day
  • diarrhoea that lasts for more than three days or is bloody
  • fever

If you suspect you are suffering from food poisoning consult your GP (or NHS Direct) for medical advice. You might be asked to submit a sample (faecal). Samples are useful because they can be used to identify the organism that caused the problem.

Preventing further illness

Maintaining good personal hygiene is crucial in preventing the spread of further illness.

If you or a close contact are unwell it is recommended you:

  • Wash your hands thoroughly after using the toilet and before handling food.
  • Wash you hands after contact with a sick person and after clearing up any soiling accidents.
  • Clear up any such accidents straight away, use hot soapy water and a disinfectant.
  • Wash door and toilet handles with a detergent and disinfectant.​

If a person with symptoms is a food handler, or clinical and social care staff who has direct contact with or contact through serving food, with highly susceptible patients or persons in whom an intestinal infection would have serious consequences, they cannot return to work for 48 hours after they are symptom free.
They must also inform their employer of their symptoms.

Children aged under five years who attend pre-school groups or nursery, or children or adults unable to implement good standards of personal hygiene, should also stay away from school or similar establishments until 48 hours after they have been symptom free.

Further investigation

Once a food poisoning notification is received, we will normally contact the person with the symptoms to ask them questions about:

  • what and where they've eaten prior to their illness.
  • whether there is any of the food that might have made them ill remaining.
  • details of their symptoms.
  • whether they've been on holiday abroad or travelled recently.
  • whether or not they have submitted a faecal sample to their GP.
  • whether anybody else they ate with also experienced any symptoms.

We may request that a person provides a faecal sample. ​

Further information

The NHS website has further information about the symptoms of food poisoning and when to seek medical advice.

The NHS website also has information about treating food poisoning

Public Health England produce a variety of publications and information on gastrointestinal illness and specific organisms associated with food poisoning.