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Food poisoning and infectious diseases

Food poisoning is a name given to a group of infectious diseases that cause similar symptoms and are associated with food.

If you suspect you have food poisoning the table below may help you identify the cause of your symptoms.  

Bacteria  Source and transmission Symptoms Onset period Recovery
 Salmonella
  • raw and undercooked food, particularly meat, poultry and eggs
  • occasionally occurs through person to person contact
  • utensils, work surfaces and hands

 

  • diarrhoea
  • nausea
  • vomiting
  • stomach pain/cramps
  • high temperature
  • headache
  • malaise
12 to 72 hours 

1 to 7 days 

 Campylobacter
  • contaminated food, milk or water
  • exposure to infected farm animals or pets
  • person to person spread is unusual but occasionally occurs within a household
  • diarrhoea
  • stomach pains
  • sickness
  • high temperature

Usually 2 to 5 days

1 to 3 weeks 

 E.coli
  • contaminated foodstuffs; beef and beef products, milk or raw vegetables
  • another person by direct contact, especially in nurseries, infant schools and households
  • contact with infected animals
  • untreated drinking water
  • diarrhoea (blood and mucus)

More severe symptoms may develop in some cases:

  • abdominal pain
  • raised temperature
  • shivering
1 to 6 days 1 to 2 weeks 
 Rotavirus
  • faecal oral route
  • spreads easily among infants by contaminated hands, toys, food and water
  • vomiting
  • diarrhoea
  • stomach cramps
  • occasional fever and convulsions
 1 to 5 days 4 to 6 days
Cryptosporidium
  • can spread by animal to human or human to human contact
  • exposure to contaminated water or land
  • consumption of contaminated water and food
  • contact with infected animals
  • public water supplies and contaminated food
  • frequently associated with foreign travel
  • Faecal oral transmission
  • watery diarrhoea which can range from mild to severe
  2 to 10 days

Up to 4 weeks 

Giardia
  • faecal oral in young children
  • direct contact with infected animals and humans
  • consumption of water, food or drinks contaminated by the faeces of infected humans or animals
  • many cases are associated with recent foreign travel
  • diarrhoea
  • abdominal cramps
 5 to 25 days 1 to 3 weeks
Norovirus
  • person to person by the faecal oral route
  • contaminated food and water
  • also risk of infections from aerosols and projectile vomit
  • vomiting
  • diarrhoea
  • fever
 24 to 48 hours 1 to 3 days
Dysentery/Shigella

 

  • water contaminated by human faeces
  • eating food washed with contaminated water
  • faecal oral

 

  • diarrhoea sometimes with blood and mucus
 1 to 7 days 5 to 7 days
Typhoid and paratyphoid
  • eating or drinking heavily contaminated food or water
  • person to person contact after hands become contaminated
  • almost all cases are acquired abroad
  • fever
  • abdominal discomfort
  • constipation
  • rashes

 7 to 14 days 

Can be as long as 30 days in some cases

Usually 3 to 4 weeks

Most food poisoning bacteria does not cause illness until 12 to 36 hours after they have entered the body.

Some illnesses can take up to seven days before you show any symptoms. 

It will hardly ever be what you ate last that made you ill, but rather what you ate yesterday or the day before.

Norovirus, also known as the Winter Vomiting Bug, is the most common stomach bug in the UK, but is not caused by contaminated food by bacteria. It is transmitted by contact with contaminated surfaces or objects, close contact with an infected person or the consumption of food handled by an infected person who has not washed their hands.

Further food poisoning advice

Reporting food poisoning

If you suspect you are suffering food poisoning it is recommended that you visit your doctor as soon as possible, who might ask you to submit a sample for examination. 

Speak to your doctor immediately if:

  • the person affected is a baby or elderly
  • the person affected has an existing illness or condition
  • symptoms are prolonged or severe (for example, bloody diarrhoea)


If you or a family member are suffering from the symptoms of food poisoning:

  • wash your hands after contact with the sick person, and before handling food
  • do not use the same towel or face cloth
  • clear up soiling accidents straightaway, wash with hot soapy water and disinfect with a disinfectant or bleach
  • disinfect door and toilet handles, taps and the toilet seat after use and disinfect the toilet bowl frequently
  • drink plenty of fluids while you are ill to prevent dehydration

If they are a food handler or health care/nursery worker who has contact with food, they should not return to work until they are symptom free for 48 hours. They must also tell their employer about their symptoms.

Parents or guardians are advised to keep children away from school or other establishments until they have been symptom free for 48 hours.

How do we investigate cases

Public Health England usually notify us of confirmed cases of food poisoning and infectious diseases. To prevent the spread of the illness our environmental health officers may decide to investigate.

We will try to contact the person(s) with the symptoms to discuss where and what they have eaten over the three days prior to you feeling ill, whether they have recently been abroad and whether their GP has taken a faecal sample.  

If we can link your illness with another case in the area, we will visit suspect premises. 

However, with only one case it is hard to prove any particular premises to be at fault. A large number of food poisonings are thought to occur in the home.

Outbreaks

The evidence we collect gives us a better chance of identifying where the outbreak came from.

We can take steps to limit the outbreak and consider what further action to take.

With institutional outbreaks we try to work to limit the spread of infection.

In schools and nurseries this means making sure:

  • no children attend who are still suffering from symptoms
  • nursing and care homes have appropriate isolation practices in place

Institutions should have their own outbreak control plan. 

In these premises two or more cases of illness qualifies as an outbreak. 

Preventing food poisoning

The following tips will help to reduce the risk of food poisoning at home:

  • defrost food thoroughly before cooking
  • ensure reheated food is piping hot
  • cover raw meat and store it at the bottom of the fridge to avoid it touching or dripping onto other foods
  • wash salad before eating it
  • avoid drinking untreated water
  • clean work surfaces, utensils, chopping boards and cloths thoroughly
  • wash hands with hot soapy water to prevent contamination. Hand washing tips
  • keep pets away from the kitchen when preparing food
  • keep your fridge under 5 degrees centigrade