Food Poisoning & Infectious Diseases

Despite everyone's best efforts, sometimes people become ill through no fault of their own. In order to help identify the cause of certain food poisoning and infectious disease outbreaks, environmental health officers will undertake an investigation.

The decision as to whether or not to carry out an investigation will depend on the cause of the illness, whether a positive result confirming an infectious disease has been received from the laboratory, the number of people affected, the severity of the illness, and any delay between the start of the illness and receipt of the report.

Where a decision has been made to investigate, the environmental health officer will contact the person(s) with the symptoms, either by post, telephone or by visiting them and will ask them questions regarding:

what and where they've eaten prior to their illness
details of their symptoms
whether they've been on holiday abroad
whether or not their GP has taken a faecal sample and
whether anybody else they ate with also experienced any symptoms. We may request that person to provide a faecal sample.

Bacteria and symptoms

The incubation period (time taken from becoming infected to feeling unwell) varies with each type of organism and in some cases can be as long as two weeks or more. If you suspect you are suffering from food poisoning, it is important to realise that the last meal you ate may not be the cause of your symptoms. The chart below gives details on incubation periods and symptoms.

Bacteria and symptom chart
Bacteria	Source	Vehicle	Route	Symptoms	Onset Period	Recovery
Salmonella	Poultry, meat, raw egg products, human and animal excreta, carriers.	Utensils, work surfaces, hands.	Contamination from raw to cooked / ready-to-eat food.	Diarrhoea, vomiting, fever.	6 to 72 hours. Usually 12-24 hours	1 to 7 days
Staphylococcus Toxin	Skin, nose, spots and boils.	Hands, coughs, sneezes, open infected wounds.	Cooked / ready-to-eat food.	Vomiting, diarrhoea, abdominal cramps	2 to 6 hours	Rapid
Campylobacter	Animals, including domestic pets, birds, contaminated water.	Raw or undercooked meat especially poultry, unpasteurised milk, bird pecked milk on doorsteps, untreated water, pets with diarrhoea.	Undercooked foods, faecal-oral route.	Abdominal cramp, diarrhoea, often bile stained. Vomiting uncommon.	1 to 11 days (usually 2 to 5 days)	3 days to 3 weeks
Bacillus Cereus	Cereals, environment	Dirty surfaces, hands, utensils.	Cooked rice, corn flour, sauces	Acute vomiting, some diarrhoea.	8 to 16 hours	12 to 48 hours
Clostridium Perfringens	Animal excreta, human excreta, raw meats, soil and dust.	Soil, dust, utensils, work surfaces, hands, unwashed vegetables and fruit.	Warm storage, slow cooking, braised, stewed and steamed foods.	Abdominal pain, diarrhoea.	8 to 22 hours (usually 12 to 18 hours)	12 to 48 hours
Clostridium Botulinum	Soil, meat, fish, including smoked.	Imperfectly processed canned and bottled foods	Airtight packaged food for example: canned and bottled foods	Fatigue, dizziness, headache, possible death	12 to 96 hours (usually 12 to 36 hours)	Very slow, can be fatal
E Coli	Animal and human excreta, water.	Hands, utensils, surfaces.	Raw foods to cooked / ready-to-eat foods.	Diarrhoea (mucus and blood)	1 to 6 days	1 to 5 days
Cryptosporidium	Animal and human excreta, contaminated water.	Contact with infected animals, humans, water.	Contact with infected animals, humans, water.	Profuse, watery diarrhoea.	2 to 5 days	Up to 4 weeks
Giardia	Animal and human excreta.	Hands, surfaces, water.	Person to person.	Diarrhoea, abdominal cramps.	5 to 25 days	Up to several weeks

Not all cases of infectious disease are due to contaminated food, many are caused by viruses that often have the same symptoms of food poisoning and spread very quickly from one person to another. These types of infection are especially common in babies and young children who pick them up from other children at nurseries, playgroups and school. Other sources of infection include farm animals and household pets.

What should I do if I suspect I have food poisoning?

If you suspect you are suffering from an infectious disease, including food poisoning, it is recommended that you consult your GP as soon as possible, who might ask you to submit a sample for examination.

If a person with symptoms is a food handler or health care/nursery worker who has direct contact or contact through serving food, with highly susceptible patients or persons in whom an intestinal infection would have serious consequences, they should not return to work until they are symptom-free for 48 hours. They must also inform their employer of their symptoms.

Parents or guardians of children aged under 5 years or children or adults unable to implement good standards of personal hygiene, are advised to keep them away from school or other establishments until they have also been symptom-free for 48 hours.

The main causes of food poisoning

The main causes of food poisoning are:

preparing foods too far in advance
not cooking foods properly
not defrosting foods correctly
storing foods incorrectly (ie too warm) so that bacteria is able to quickly grow
cross contamination of foods after cooking
infection from people handling foods due to poor hygiene.

How do I avoid food poisoning

Whilst different types of germs and foodstuffs are associated with different types of illness, by following some simple rules you can help yourself and your families to stay safe:

Always store raw meat and poultry in a covered container at the bottom of the fridge so that it cannot drip onto other foods.
Ensure that your fridge is clean and operating between 0 and 4 degrees centigrade
Always defrost meat, fish and poultry thoroughly before cooking.
Cook food thoroughly and if reheating, ensure it is piping hot before eaten.
If hot food is not to be eaten immediately, cool it quickly (within 90 minutes and refrigerate).
Ensure that work surfaces, cloths, utensils and chopping boards are cleaned thoroughly (between use) especially after being used for raw meat, poultry or fish.
Keep any cuts/wounds covered with a waterproof dressing when preparing food.
Always wash salad before eating it to remove dirt.
Keep dogs, cats, etc. out of the kitchen when preparing food and always wash their bowls separately to yours.
Always wash your hands with soap and hot water before preparing food or handling a baby, after going to the toilet, after playing with pets, after changing nappies, caring for people suffering from diarrhoea or vomiting, handling soiled bedding, etc.
Never drink untreated water from lakes or streams as it may be polluted.

Further information

Gov.uk website - Infectious Diseases