Food poisoning

Campylobacter jejuni
© A. Dowsett, Health Protection Agency / Science Photo Library The bacterium Campylobacter jejuni is a common cause of food poisoning. Contaminated poultry, meat and milk are sources of infection. It takes about 3 days for the symptoms of diarrhoea, stomach cramps and fever to develop.

The number of cases of food-borne illness remains high with an estimated 1 million people in the UK becoming infected each year. The symptoms, including vomiting, diarrhoea, abdominal pain and fever, are not only unpleasant; they also cost an estimated £1.5 billion a year in lost working days and medical care. Most food-borne illness is preventable.

Preventing food poisoning is the responsibility of everyone in the chain from the plough to the plate. This includes farmers and growers, manufacturers, shops, caterers and consumers. The activities of food suppliers are governed by UK and EU food safety law. In the home correct hygiene, cooking and storage must be practised.

Some of the bacteria that can cause food poisoning

Name of bacterium Original source Risky foods Time to develop Symptoms
Bacillus cereus soil cooked rice and pasta; meat products; vegetables 1–5 hours nausea, sickness and diarrhoea
Campylobacter jejuni raw meat and poultry undercooked meat and poultry; raw milk and cross-contaminated food 3–5 days of eating infected food fever, severe pain and diarrhoea
Clostridium botulinum (very rare) soil faulty processed canned meat and vegetables; cured meat and raw fish 1–7 days affects vision, causes paralysis and can be fatal
Clostridium perfringens the environment large joints of meat; reheated gravies 8–24 hours nausea, pain and diarrhoea
Escherichia coli –
E. coli O157:H7 is a very nasty strain and it can be fatal
the gut of all humans and animals contaminated water, milk, inadequately cooked meat, cross-contaminated foods 3–4 days inflammation, sickness and diarrhoea
Listeria monocytogenes everywhere soft cheeses, paté, pre-packed salad; cook-chill products varies fever, headache, septicaemia and meningitis
Salmonella gut of birds and mammals including humans - spread by faeces into water and food poultry, eggs and raw egg products, vegetables 6–48 hours diarrhoea, sickness and headaches
Staphylococcus aureus the skin and noses of animals and humans cured meat; milk products; unrefrigerated, handled foods 2–6 hours sickness, pain and sometimes diarrhoea

An in-depth look at a bacterium that causes food poisoning


The bacterium Campylobacter is part of the normal flora living in the intestines of healthy chickens and other animals. At the factory when a chicken is killed and gutted, the contents of its intestines, including the Campylobacter, could come into contact with the bird’s skin. This means the raw chicken meat could become contaminated with Campylobacter.

How do you make sure chicken is safe to eat?

Campylobacter is sensitive to heat so cooking the chicken properly will kill it and make the meat safe to eat. If the chicken is served undercooked, then the Campylobacter could survive and be eaten along with the chicken. After the bacteria have been swallowed they multiply inside the person’s intestine and cause the illness known as food poisoning. It takes about 3 days for the symptoms of diarrhoea, stomach cramps and fever to develop. The illness lasts between 2 days and a week.

Cross-contamination is the transfer of microbes from raw foods to prepared and cooked foods, it can take place by:

  • raw food touching or splashing on cooked food;
  • raw food touching equipment or surfaces that are then used for cooked food;
  • or people touching raw food with their hands and then handling cooked food.

To prevent cross-contamination it is important to maintain good kitchen hygiene such as storing cooked and raw food separately and good personal hygiene by washing hands correctly and tying hair back.

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