Food poisoning

What is food poisoning? 

Food poisoning is an illness, usually caused by eating or drinking food or water contaminated by bacteria (germs) or the poisons that they produce.

It can be caught from food eaten at home, at restaurants, abroad, etc.

The common symptoms associated with food poisoning include:

  • diarrhoea
  • vomiting
  • nausea and
  • stomach cramps

These usually occur within two to 36 hours of consumption of the food, although with some types of food poisoning, illness may not occur for days or even weeks.

The last thing eaten is not necessarily the cause of the food poisoning. The symptoms usually last between one and seven days, although this may be longer.

All the time you have the symptoms, and in some cases for some time after, you can transmit the infection to other people if you are not careful.

Food poisoning can only be confirmed by laboratory testing and so you should contact your local GP regarding providing a stool sample, which can be sent for analysis.

If the sample is positive for a food poisoning bacteria, Public Health England are informed, who in turn ask our Food and Safety Team to try to identify a source of infection.

We would then contact you to identify what foods you have eaten and from where they were purchased.

Please note that we are unable to carry out a formal investigation if you have not seen your GP and submitted a faecal specimen for analysis.

Food poisoning is mainly caught from contaminated food or water.

The common causes of food poisoning are:

  • under cooked meat or poultry
  • inadequate temperature control of food
  • food contaminated by raw meat or poultry
  • food contaminated by food handlers with unclean hands
  • food contaminated by unclean equipment
  • cleaning surfaces and equipment with dirty clothes

Incorrect storage, handling, preparation and cooking of food can lead to food poisoning in your own home, as well as in food businesses.

Unfortunately, contaminated food usually looks, smells and tastes fine, so you cannot tell that it is contaminated.

Doctors have to notify our Food & Safety Team about cases of certain infectious diseases, including food poisoning, and we have a duty to investigate such cases.

We try to establish the cause of the food poisoning, and we follow this up where necessary by inspecting food premises to help prevent other people suffering from food poisoning.

We also provide advice on precautions which should be taken, especially to people in groups where there is a high risk of passing on the infection. This includes food handlers, young children and people who look after the very young, the elderly or the ill.

Even when the symptoms have cleared, you may still carry and excrete the bacteria for several weeks. Close contacts to the ill person may also carry and excrete the bacteria, even though they have had no symptoms.

With some types of food poisoning, people in the high risk groups, mentioned above, who are carrying the bacteria, must not return to work until they have been cleared by ourselves.

Take care with your hygiene, and in particular, wash your hands thoroughly:

  • after using the toilet
  • before handling food and
  • before eating or feeding others.

We would also recommend increased cleaning of touch surfaces such as toilet seats and handles, light switches and door handles.

If you are a food handler, healthcare worker or work with the elderly or children under five years old, do not return to work until you have checked with us, by contacting the Food & Safety Team using the details below.

Food handlers suffering from food poisoning must report this matter to the Environmental Health Service or their employer, by law.

If you are not included in the above list of people, generally you can return to work when your symptoms have cleared, unless the Environmental Health Service or your doctor tell you not to.

Children should not return to school until 24 hours after the first normal stool, or in accordance with your school’s policy, and children attending nursery, when their symptoms have cleared for 48 hours.

Personal hygiene

  • Wash hands thoroughly: before and after handling food, especially after handling raw meat and poultry; after using the toilet; after changing nappies and handling soiled clothing; after touching animals, especially before handling food.
  • Cover open cuts and sores which may come into contact with food with waterproof plasters.
  • If possible, do not prepare food for other people when suffering from food poisoning symptoms.

General hygiene

  • Maintain high standards of hygiene in the kitchen. Keep kitchen surfaces and equipment clean and use anti-bacterial cleaning materials where possible.
  • Keep cooked foods and uncooked foods, especially raw meat and poultry, separate. This will also include using separate chopping boards, plates and knives.
  • Keep pets out of the kitchen when preparing food, and keep them off work surfaces.
  • Use pasteurised or UHT milk and cream.
  • When travelling abroad, check beforehand that water and ice is safe to consume. If it is not, or if in doubt, make sure it is sterilised using chlorine tablets for example, or buy bottled water.
  • Additionally, avoid eating salads and raw fruit / vegetables that have been washed with non-sterilised water in countries where the water is not safe to consume.
  • If you are sick, elderly, pregnant or susceptible to infections, or are preparing food for such people, toddlers or babies: avoid raw / undercooked eggs; avoid soft cheeses; reheat cook-chill meals until piping hot.

Temperature control

  • Keep all perishable foods in a refrigerator.
  • Your fridge should operate at below 5C to prevent bacteria growing.
  • Store cooked or ready-to-eat foods above raw meat and vegetables.
  • Ensure frozen foods, especially meat and poultry, are fully thawed before cooking.
  • Ensure food is cooked thoroughly.
  • Cool food quickly and refrigerate as soon as possible after cooking.
  • If reheating food ensure that it is piping hot.


  • Source: Poultry, meat, raw egg products, human and animal excreta and carriers
  • Vehicle: Utensils, work surfaces and hands
  • Route: Raw to cooked / ready-to-eat food
  • Symptoms: Diarrhoea
  • Onset period: 6 to 36 hours. Usually 12 to 24 hours
  • Recovery: 1 to 7 days

Staphylococcus Toxin

  • Source: Skin, nose, spots and boils
  • Vehicle: Hands, coughs, sneezes and open infected wounds
  • Route: Cooked / ready-to-eat food
  • Symptoms: Vomiting, diarrhoea, pain and cramps
  • Onset period: 2 to 6 hours
  • Recovery: Rapid


  • Source: Animals (especially dogs), poultry and dairy products
  • Vehicle: Hands and undercooked poultry, pork and eggs
  • Route: Undercooked foods and faecal-oral route
  • Symptoms: Abdominal cramp, diarrhoea and often bile stained
  • Onset period: 2 to 11 days
  • Recovery: 3 days to 3 weeks​

Bacillus Cereus

  • Source: Cereals and environment
  • Vehicle: Surfaces, hands and utensils
  • Route: Cooked rice, corn flour and sauces
  • Symptoms: Acute vomiting and some diarrhoea
  • Onset period: 1 to 16 hours
  • Recovery: 12 to 48 hours

Clostridium Perfringens

  • Source: Animal excreta, human excreta, raw meats and dehydrated products
  • Vehicle: Soil, dust, utensils, work surfaces, hands and unwashed vegetables and fruit
  • Route: Warm storage, slow cooking, braised, stewed and steamed foods
  • Symptoms: Abdominal pain and diarrhoea
  • Onset period: 8 to 22 hours
  • Recovery: 12 to 48 hours

Clostridium Botulinum

  • Source: Soil, meat and fish, including smoked
  • Vehicle: Imperfectly processed canned and bottled foods
  • Route: Canned and bottled foods
  • Symptoms: Fatigue, dizziness, headache and possible death
  • Onset period: 24 to 96 hours
  • Recovery: Very slow, can be fatal

E Coli

  • Source: Human excreta and water
  • Vehicle: Hands, utensils and surfaces
  • Route: Raw foods to cooked / ready-to-eat
  • Symptoms: Diarrhoea (mucus and blood)
  • Onset period: 12 to 72 hours
  • Recovery: 1 to 5 days

More information on food poisoning can be found of the Food Standards Agency website.






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