Food poisoning

E. coli is the abbreviated name of the bacteria called Escherichia coli, which are a normal inhabitant of the large intestine of mammals and birds. The human intestine contains many bacteria necessary for us to maintain a normal and healthy life. However, certain strains of E. coli known as verocytotoxin-producing E. coli (VTEC), produce a potent poison, or toxin, which causes illnesses ranging from mild diarrhoea through to very severe inflammation of the gut. Occasionally this can cause complications such as kidney failure, and anaemia. The most important toxin-producing strain associated with human illness is known as E. coli O157.

How do you get infected with E.coli O157?

E. coli O157 bacteria are commonly found in the gut of cattle and other farm animals.

You can become infected by:

• eating infected food, mainly meat, unpasteurised milk and cheese.
• contact with infected animals, either directly or through inadvertent contact with animal faeces, for example at farms, petting farms and campsites.
• contact with other people who have the illness, through inadequate hand washing after using the toilet, and/or before food-handling, particularly in households, nurseries and infant schools.
• eating unwashed vegetables which may have been infected by manure from infected cattle.
• drinking water from inadequately treated water supplies (rivers, streams, well water)
• swimming or playing in infected water (rivers, streams, ponds etc.)

How can you avoid getting infected with E. coli O157?

Handle food and drink safely

• Fully cook minced meat products like beefburgers, meatballs, meat loaf etc.so that they are coloured all the way through, and no blood runs from them.
• Keep cooked and uncooked meats separately; store uncooked meat on the bottom shelf of the fridge to avoid dripping raw meat juices onto other food.
• Never put cooked food back on a plate which has had fresh uncooked meat on it.
• Thoroughly wash all salads and vegetables that are to be eaten raw.
• Avoid eating and drinking unpasteurised milk and dairy products.
• Boil any drinking water if you are unsure of its source.
• Do not swim in water that may be contaminated by cattle and sheep in nearby fields.

VTEC are very infectious because very few bacteria are needed to cause illness. This means that disease can spread easily within families and in other settings such as day nurseries, primary schools, nursing homes and hospitals where there are young children and others who might have difficulty in keeping clean.

Personal hygiene is essential. Thoroughly wash hands after using the toilet, handling raw meat, before meals and after contact with animals. Ensure children wash their hands with warm water and soap after contact with animals, particularly while on farm visits.

If someone has E. coli infection, wash all dirty clothes, bedding and towels in the washing machine on the hottest cycle possible. Clean toilet seats, toilet bowls, flush handles, taps and wash hand basins after use with detergent and hot water, followed by a household disinfectant.

If you have E. coli infection you should not prepare food for others.

You should take special precautions on farm visits – see below.

What are the symptoms of E. coli O157, and how long do they last?

People infected with E. coli O157 can have one, some, or all of the following symptoms: diarrhoea – about 50% of people also have blood in their stools; stomach cramps; fever.

Some infected people may have mild diarrhoea or no symptoms at all. A very small number of patients may develop ‘haemolytic uraemic syndrome’ (HUS) which is associated with kidney failure, anaemia, and bleeding. Complications are more common in children under five years of age and the elderly.

On average, it takes three to four days for symptoms to develop after swallowing an infectious dose of E. coli O157. Symptoms can last up to two weeks, except in cases with complications. Most people get rid of the bacteria after about one week although children may continue to carry it for longer periods.

How do you treat E. coli O157 infection?

There is no specific treatment for E. coli O157 infection. It is important to drink plenty of fluids as diarrhoea can lead to dehydration and you can lose important sugars and minerals from your body. Your doctor may recommend a re-hydration solution, available from your pharmacist.

• If you feel sick, try taking small sips of fluid, frequently.
• Avoid tea, coffee, carbonated drinks or alcohol.
• Always dilute sugary drinks even if you would not normally dilute them.
• A simple painkiller like paracetamol can help combat any pain

Antibiotics are not recommended and are likely to increase the risk of getting complications such as haemolytic uraemic syndrome (HUS). When complications develop, patients need to be admitted to hospital.

How long should you stay away from work or school?

Most adults, and children over five years, can go back to work or school 48 hours after the first normal stool.

Children under five must stay away from nurseries and playgroups until they are shown to be completely clear of the bacteria and free from diarrhoea.

You must tell your employer if you have had E. coli O157 infection if you handle food, or work with vulnerable groups such as the elderly, the young, or people in poor health. These groups should stay off work until two further stool tests, at least 48 hours apart, show that the bacteria have cleared.

Also if you are a contact of a case and work in any of the above groups you may have to be excluded whilst a stool test is conducted to make sure you have not acquired the bacteria.

Public Health England

We provide advice on controlling outbreaks. We work with Environmental Health Officers who look for the source of the infection; for example the food that is responsible, outbreaks linked to farm animals or the environment, so that we can help to prevent other people from becoming infected. We also monitor outbreaks of E. coli O157 and look for any patterns or trends which show possible connections between the people who are affected.

Where can I get further advice?

If you have concerns about your health see your family doctor.

There is also information on the Public Health England website

How to avoid E coli O157 on farm visits

On farm visits you must:

• avoid touching faces or putting fingers in mouths while in farm environments
• don’t kiss farm animals or allow children to put their faces close to animals
• wash hands thoroughly with soap and water after touching animals, fences or other surfaces in animal areas
• don’t eat or drink while touching animals or walking round the farm and only eat and drink in picnic areas or cafes
• wash hands thoroughly with soap and water before eating or drinking
• remove and clean boots or shoes that might have become soiled and clean pushchair wheels then wash hands thoroughly with soap and water
• don’t use gels or wipes instead of washing hands with soap and water - gels and wipes don’t remove E. coli O157
• supervise children closely to make sure they wash their hands thoroughly