Food Poisoning

The Food Standards Agency estimates that there are over 800,000 cases of food poisoning in the UK each year. Most cases of food poisoning are mild; however, some cases are much more serious and in some cases, may prove fatal (around 500 lives are lost each year because of food poisoning). If you have been affected by food poisoning as a result of eating food from a restaurant or cafe or a public caterer you should report this to your local Environmental Health department; they will conduct an inquiry and assess whether the establishment should improve their hygiene standards.

What causes food poisoning?

It is possible that food may become contaminated at any point during production, preparation and cooking. Possible causes of food poisoning include:

  • Under cooking food
  • Cooking food at the wrong temperature
  • Not storing or chilling food at the right temperature
  • Eating food that is passed its sell by date
  • Eating food that has been prepared by a person that hasn’t washed their hands
  • Cross contamination: this occurs when bacteria are transferred between surfaces, objects, equipment and people

Contamination can be caused by a number of different sources; these include bacteria, viruses, toxins and parasites. In most cases, contamination is caused by bacteria; common types of bacteria associated with contamination include:

  • Campylobacter: this form of bacteria is the most common cause of food poisoning; it is commonly found in raw meat, untreated water and raw poultry
  • Salmonella: this is probably the most well-known cause of food poisoning; commonly, salmonella is found in raw meat, poultry and uncooked eggs.
  • Listeria: listeria can be found in a huge range of foods, from ready-made sandwiches and pate to butter and smoked salmon
  • E.coli (Escherichia coli): harmful strains of the E.coli bacterium are usually found in unpasteurised milk and raw beef

Contamination can also be caused by viruses, including the rotovirus and norovirus; these viruses are passed on from humans, usually by direct contact with the food (this is particularly common when people do not wash their hands after going to the toilet and then start preparing food).

Less common sources of contamination include toxins and parasites; parasites are usually passed from animals to humans, either by contamination from animal faeces or undercooking meat; the most common type of parasitic food poisoning is known as toxoplasmosis. Contamination by toxins is usually restricted to oily fish, including salmon, tuna, mackerel, sardines and trout; the risk is very low. Pregnant women should avoid fish that have a high mercury content including shark, marlin and swordfish; mercury can cause harm to the foetus.  

Symptoms of food poisoning

Some people may experience symptoms very quickly after eating, while some people may have symptoms that develop over a much longer period of time. In most cases of food poisoning the incubation period is around 2-3 days. Most people with food poisoning experience these common symptoms:

  • Nausea
  • Vomiting
  • Diarrhoea

Other possible symptoms include:

  • A raised temperature
  • Abdominal pain
  • Pain in the muscle
  • Loss of appetite
  • Stomach cramps

Should I see a doctor?

Most people only experience symptoms for a short time and recover quickly; however, some cases are more serious. You should see your doctor if:

  • You are sick regularly for more than 48 hours
  • You have traces of blood in your vomit
  • You cannot keep fluids down for more than 24 hours
  • You have a seizure
  • You experience double vision
  • You experience problems with your speech
  • You have diarrhoea for more than 3 days
  • You show symptoms of moderate or severe dehydration, including a dry mouth, sunken eyes and troubles urinating
  • You experience changes in your mental state and start to feel confused

How is food poisoning treated?

Many patients do not use any treatment when they have food poisoning, as most symptoms pass quickly; however, it is important to remember to take in plenty of fluids if you are regularly being sick or have diarrhoea. If you have been unable to keep water down and are dehydrated you may be advised to take oral rehydration salts; these usually come in sachets, which are then dissolved in a glass of water. Rehydration helps to replace salts, minerals and nutrients that are lost when the body becomes dehydrated. In extreme cases of dehydration, doctors may recommend that patients go into hospital; they will then be fitted with an intravenous drip. Symptoms that are caused by bacterial infections may be treated with antibiotic medication if the symptoms persist for longer than 3 days.  

Preventing food poisoning

The Food Standards Agency has issued guidelines to help people reduce the risk of suffering from food poisoning; these include:

  • Cleaning and hygiene: take care to clean surfaces thoroughly, wash hands frequently (especially before preparing food), clean equipment and wear special plasters if you have a cut or wound. Avoid cooking when you are ill.
  • Cooking: take care to cook meat thoroughly and only serve foods that are piping hot throughout. Avoid reheating food more than once.
  • Chilling: keep your fridge at a suitable temperature (between 0 and 5 degrees) and ensure food is wrapped up and chilled; don’t leave food out on the surfaces, especially meat and dairy products. Make sure your freezer is shut properly at all times and defrost foods before cooking them.
  • Cross-contamination: wash your hands after handling raw food and before you start to prepare food. Clean surfaces before preparing food and use different knives and chopping boards for different foods. Store raw meats at the bottom of the fridge to prevent juices dripping onto other areas of the fridge. Experts recommend that you should avoid washing raw meat as the jet of water can cause harmful bacteria to be spread to other parts of the kitchen when the water splashes.

Guide to Environmental Health

Environmental Health

Air pollution

Chemical safety

Food poisoning

Health and natural disasters

Sanitation and water

Health in the workplace


Chemical Burn

Carbon monoxide poisoning