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Food poisoning

What causes food poisoning?

Food poisoning can be caused by food or drink that is contaminated with bacteria, viruses, chemicals or toxins. The main causes of food poisoning and food borne illness are:

  • preparing foods too far in advance
  • not cooking foods properly
  • not defrosting foods correctly
  • storing foods incorrectly (too warm) so that bacteria can grow quickly
  • cross contamination of foods after cooking
  • infection from people handling foods due to poor hygiene.

Who is at risk from food poisoning?

Anyone can contract food poisoning, however, babies, young children and the elderly can become ill very quickly  and are more at risk. Pregnant women, people who already have a pre-existing illness, and anyone whose immune system is weakened can also be seriously affected by food borne illness.

What are the main symptoms of food poisoning?

The symptoms of food poisoning generally include some or all of the following:

  • diarrhoea
  • stomach cramps
  • vomiting
  • fever
  • nausea
  • headache
  • dizziness.
In extreme circumstances food poisoning can result in death, usually due to health complications or infections, particularly in vulnerable people.

Tips for prevention

Watch our video for tips on good food hygiene.

You should do the following:

  • Make sure you cook food thoroughly to destroy harmful bacteria. Follow the manufacturers' guidelines and ensure food is piping hot throughout before consumption.
  • Make sure that food prepared in advanced (e.g. buffet food) is kept refrigerated until it's needed and not left at room temperature.
  • Don't leave hot food to cool at room temperature for longer than one to one and a half hours. After this it should be transferred to the fridge.
  • When reheating food make sure that it's piping hot throughout to kill any bacteria.
  • After handling raw foods, you must wash surfaces, equipment and hands with anti-microbial soap and hot water before handling cooked foods in order to avoid cross contamination.
  • It's important to wear clean clothing and to wash your hands before you prepare food.
  • Wash your hands after going to the toilet, after touching your mouth, nose or hair and after handling animals, this helps prevent the spread of harmful bacteria.
  • Check the 'Use by' dates on food and make sure that you use the food before the date expires.
  • Keep food preparation surfaces and utensils clean and disinfected.
  • Prepare and store raw meat and 'ready-to-eat' food separately. Always keep raw and defrosting meat at the base of the refrigerator, below everything else.
  • Make sure that your refrigerator and freezer are operating properly. Invest in a suitable thermometer. The refrigerator should operate at 5°C or lower and the freezer at -18°C or lower.

What should I do if I have symptoms of food poisoning?

Food poisoning can spread quickly, partly because everyone in the family could have eaten the same food and partly because the bacteria may be picked up by close family contact (nursing the sick). 

If you suspect you're suffering from food poisoning it's recommended you visit your doctor as soon as possible. You may be asked to submit a sample for examination. Samples are useful because they might be able to show which food borne illness you're suffering from, or could rule out a food poisoning organism. Viruses can also be detected. 

Consult your doctor immediately if the person affected is a baby, elderly or has an existing illness or condition or if symptoms are prolonged or severe (bloody diarrhoea). 

How do I prevent the spread of food poisoning?

  • Wash your hands after contact with the sick person, and before handling food.
  • Avoid preparing food for other people.
  • Don't work if you work with children or the elderly.
  • Don't handle or prepare food as part of your job under any circumstances.
  • Don't return to work until 48 hours after the symptoms have ceased.
  • Don't use the same towel or face cloth as someone who is suffering with food borne illness.
  • Clear up soiling accidents straight away, wash with hot soapy water and disinfect with a disinfectant.
  • Disinfect door and toilet handles, taps and the toilet seat after use and disinfect the toilet bowl frequently.
  • Drink plenty of fluids while you're ill to prevent dehydration.

Food poisoning outbreaks

If a number of people ate at the same venue and have similar symptoms, this may be due to a food poisoning outbreak. Our investigation into the outbreak will involve:

  • interviewing people who are ill
  • interviewing others who ate at the venue but didn't have symptoms
  • taking faecal and food samples (if appropriate), and
  • inspecting the implicated venue.

If there is enough evidence implicating a food premises within the area as a possible source of the outbreak, we may decide to carry out a food hygiene inspection.

What we do

Food poisoning is infectious. If you think you've got food poisoning or a food related illness you should contact us for advice. 

As well as investigating notifications of infectious diseases (particularly food poisoning) from the general public, we'll also investigate notifications from GPs, businesses and other local authorities. 

Once we receive a food poisoning notification, we'll contact the person with the symptoms and ask them the following questions:

  • what and where they've eaten before their illness
  • details of the symptom
  • whether they've been on holiday abroad
  • whether or not their GP has taken a faecal sample, and
  • whether anybody else they ate with also experienced any symptoms
  • we may request that person provides a faecal sample.

The purpose of this investigation is to try to prevent the spread of illness within the community and try and establish possible causes.

If a person with symptoms is a food handler or health care or nursery worker who has direct contact or contact through serving food, with highly susceptible people, they can't return to work until they are symptom-free for 48 hours. They must also inform their employer of their symptoms. 

Parents or guardians of children aged under five years or children or adults unable to implement good standards of personal hygiene, are advised to keep them away from school or other establishments until they've also been symptom-free for 48 hours. 

Many different sorts of bacteria (germs) can cause food borne illness. When food is kept warm, these bacteria can grow rapidly and reach dangerous levels within hours. Good food hygiene standards in industry and the home are vital to prevent food borne illness.

The incubation period (time taken from eating the food to feeling unwell) varies with each type of organism and in some cases can be up to 10-15 days after consumption of the food. It's important to realise that the last meal you ate may not be the cause of your symptoms.

For more information on food-related illnesses, visit the Health Protection Agency's website.

Contact us
Environmental health
028 9027 0468
Food Safety
Cecil Ward Building
4-10 Linenhall Street