Food poisoning is an illness caused by eating food contaminated with harmful micro-organisms or the toxins (poisons) they produce.
Which micro-organisms cause food poisoning?
In the United Kingdom, the two most common causes of food poisoning are the bacteria known as Campylobacter and Salmonella. Other bacteria, such as Staphylococcus aureus, Clostridium perfringens, occasionally Clostridium botulinum, Shigella, Listeria and Escherichia Coli can cause food poisoning.
What are the signs and symptoms of food poisoning?
The symptoms of food poisoning include diarrhoea, abdominal pain, nausea, and sometimes vomiting and fever. The severity of the illness depends partly upon the type of organism and partly on the susceptibility of the patient; the very young, older people and those whose immune systems are compromised are particularly vulnerable. Pregnant women and their unborn babies are also vulnerable, especially to diseases such as listeriosis. Symptoms of food poisoning may start within an hour of eating contaminated food, or as long as 48 hours afterwards. They usually last a few days, depending on the severity of the illness.
How is food poisoning diagnosed?
Many people with food poisoning don’t go to the doctor and draw their own conclusions about their illness. The GP can confirm the diagnosis by sending a stool specimen to the laboratory if necessary.
What is the treatment?
Usually recovery takes place in a few days, helped by rest and plenty of clear fluids. Sachets of rehydration salts can be bought over-the-counter from the pharmacist, and may be helpful in promoting recovery. Be very careful about handwashing and hygiene. If diarrhoea is frequent, especially if accompanied by vomiting, there may be a risk of dehydration, and this is a particular problem in older people or young children and babies. The GP should be contacted if diarrhoea and vomiting are persistent, especially in these vulnerable groups as, occasionally, hospital admission is needed.
How can food poisoning be prevented?
The following guidelines may be helpful:
* Always wash your hands after visiting the toilet, changing nappies or handling animals.
* Always wash your hands before preparing food.
* Always wash your hands after handling raw meat or eggs, especially before handling other food.
* Use different chopping boards and knives for different foods – for example for vegetables and meat.
* Wash utensils and kitchen surfaces thoroughly before use.
* Keep foods in the refrigerator covered and make sure your refrigerator is below 5°C. Do not let foods such as prawns, ham and cream cakes stand at room temperature for two hours or more, before being eaten.
* Cook meat thoroughly, particularly hamburgers, leaving no pink in the middle.
* Cook chicken thoroughly until there is no pink in the middle and the juices are clear. Raw eggs, used in homemade mayonnaise and mousses for example, carry an infection risk and should not be given to vulnerable people.
* Wash fruit and vegetables thoroughly, especially if they are to be served raw.