Food poisoning

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

Campylobacter

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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  Spoilers

  When microbes grow on food it soon beings to smell nasty, look slimy, change colour, taste awful or even get a furry coating and is inedible. Find out what’s causing this.

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  Producers

  Microbes ferment sugar to make energy for themselves – luckily for us food like bread and yoghurt can be made by microbial fermentations.