Food Poisoning

What is food poisoning?

Food poisoning is the illness caused by eating food contaminated with harmful bacteria. There are many types of food poisoning bacteria that cause a variety of symptoms and which last for different periods of time.

The most common symptoms are:

• diarrhoea
• vomiting
• abdominal pain.

Food poisoning is an infectious disease which can easily be passed to other people by poor hygiene, it is confirmed through the laboratory analysis of a stool sample.

How do environmental health officers investigate?

GPs will notify Environmental Health & Licensing of any patients suffering from food poisoning. In case the patient works with food or vulnerable people, we investigate the possible causes very quickly. Affected patients are asked:

• what was eaten at least three days prior to becoming ill
• what the symptoms were and how long they lasted
• if there was any contact with other ill people or pets
• what is their occupation
• if they have recently travelled outside the UK.

This helps us find a possible cause of the illness and enables us to provide advice and guidance on how to prevent illness in the future and what precautions to take whilst ill.

It may not be due to your last meal

If you become ill either after eating at a restaurant or eating ready-cooked food bought from a shop, don't assume that this is the cause of your illness. Food poisoning bacteria take quite a long time to reproduce inside the human gut, and some people are more resistant than others, so it may be some time before there are enough to cause illness.

Very often the problem is caused by something eaten as long as two or even three days before the symptoms show, although it is possible for some food poisoning symptoms e.g. vomiting, to appear more quickly (this is usually caused by the poison or toxin which some bacteria make). If there is a lot of toxin in the food when eaten the stomach is likely to react quite quickly by vomiting to try to remove the poison. This can happen within a few hours of eating the affected food.

What to do if you think you are suffering from food poisoning?

• report it to your doctor and provide a stool sample
• report it to |Environmental Health & Licensing so that we can investigate
• report the incident to your employer if you work with food or vulnerable people.

How does food poisoning occur?

Food poisoning bacteria are living organisms that can only be seen through a microscope. Bacteria are present everywhere - in soil, water, dust, in the air and they can also live in human and animal intestines. Given the right conditions bacteria multiply very rapidly. These conditions include:

• Time - in ideal conditions one bacterium can multiply to over two million within seven hours.
• Warmth - food poisoning bacteria grow best in a temperature of 5ºC to 63ºC (the danger zone).
• Food - The types of food bacteria prefer include: ready-to-eat dairy and egg products, meat, poultry, fish and shellfish. In these high-risk foods bacteria multiply rapidly.
• Water - Bacteria require moisture to grow so drying is a good form of food preservation.

How can food become contaminated?

Food can be contaminated by unhygienic food handling and storage.

Precautions:

• Separate raw foods from those which are ready to eat, to prevent cross-contamination.
• Wash thoroughly any utensils, equipment and your hands after handling raw foods, to prevent bacteria passing onto ready-to-eat foods.
• People who prepare and serve food can pass on food poisoning bacteria by poor personal hygiene, so hand washing with hot water and soap and thorough hand drying is very important.

How can food poisoning be prevented?

• stop food from becoming contaminated
• stop the bacteria in food from growing and multiplying
• kill bacteria found in raw food by thorough cooking.

Food poisoning is the result of a chain of events:

• bacteria on the food
• warmth, moisture and food to grow
• time to grow and multiply.

To break the chain of events and prevent food poisoning:

• Do wash and dry hands thoroughly before touching food (raw or cooked), after going to the toilet, smoking or touching pets.
• Do wash thoroughly all equipment used for preparing foods (particularly raw food).
• Do store perishable food below 5ºC - always keep food at a temperature outside the danger zone (5ºC - 63ºC).
• Do make sure food is cooked until it is piping hot (75ºC).
• Do make sure food is served as soon as possible after preparation.
• Do not handle food if you are suffering from diarrhoea and/or vomiting.
• Do not store cooked foods below raw foods in the refrigerator.

Further information

• |Food Safety Week campaigns
• |Campylobacter information
• |Cryptosporidium information
• |E-coli information
• |FSA - E-coli cross-contamination guidance
• |Giardia information
• |Listeria information
• |Salmonella information
• |Shigella information
• |Food Poisoning in Residential and Care Homes
• Contact |Environmental Health & Licensing