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Food poisoning

The Council's Environmental Health Officers routinely investigates cases of food poisoning and other notifiable infectious diseases. These are usually reported to the Council by the Public Health England following receipt of positive results from their laboratory. This normally arises as a result of people contacting their GP and submitting a faecal sample for examination.  The reason for investigation is to give the person, or the person's carers more information in an attempt to ascertain what may have caused the illness (this can be very difficult to establish with any certainty). Also it can help obtain information that may be able to assist us in our inspections of food businesses and food sampling programme.

The Council's Environmental Health Officers may decide to investigate the notification to try to prevent the spread of the illness within the home and the community and try to establish the source of the infection. 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 by post 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.

The main causes of food poisoning are:

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


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.

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, household pets, birds and water.

For further details on the most common bacteria and symptoms please click on the links below:


Is one of the most common food poisoning bacteria in the UK. It is commonly associated with poultry and raw meat but they have been associated with pets as well. The effects of Campylobacter are nausea and diarrhoea and in some instances vomiting. This usually occurs 2-5 days after eating contaminated food. Cooking food (poultry and meats) will kill campylobacter.


Another common food poisoning bacterium is Salmonella and is found mainly in poultry, meat, eggs and dairy. Other sources can be pets including  tortoises and terrapins. Typical symptoms include nausea, fever and vomiting, The onset time after eating contaminated food is usually between 12-72 hours (half a day to three days after eating. Cooking foods will kill Salmonella.

E.Coli (VTEC 0157) 

E.Coli can be easily transmitted by not  washing hands after WC as it is commonly found insewage, animal guts, beef and raw milk and raw vegetables. Onset time 1-6 days (can be up to 10 for E. Coli 0157), also farms and zoos where people can touch animals.  Symptoms abdominal pain, fever, diarrhoea, vomiting and with 0157 – kidney failure and possibly death.

Clostridium sp.  

Clostridium Perfringens is one of the most common food poisoning organisms in USA.  It is commonly found in soil and dust, beef, poultry and gravyOnset time – 6- 24 hours after eating contaminated food symptoms include diarrhoea and abdominal cramps (not fever or vomiting)

Listeria Monocytogenes 

Listeria is found in soil, untreated water, sewage and people.  It is found in – soft cheese made from unpasteurized milk, salad vegetables and pâtéOnset time 3- 70 days(but times have been between 1 – 90 days).  Symptoms – flu like. At risk groups include pregnant mothers who can pass the infection on to their baby.


Cryptosporidium is a parasite which infects the bowels and causes diarrhoea and vomiting. At risk groups are those who are immuno-compromised . People who are infected pass out the cysts of the bacteria and must stay away from swimming pools until at least 14 days after infection has passed. It is found in contaminated water, food, faeces and soil. It can takle between 3 – 12 days for symptons to develop and these usually last between 12-14 days.


Giardia is a parasitic infection often caused by drinking of contaminated water, or being in contact with someone who has Giardiosis and has not washed their hands properly after visiting the toilet. Often there are no symptoms and the bodies immune system will clear it out, however if not then they may develop 1-2 weeks after infection. Symptoms may be explosive and watery diarrhoea and abdominal pain,


Food Poisoning Outbreaks

If a number of people ate at the same venue and have the same food   poisoning-type symptoms, this may be due to a food poisoning outbreak. Our investigation into the outbreak will involve:

  • interviewing people who are ill
  • interviewing others who ate at the venue but didn't have symptoms taking faecal and food samples (if appropriate)
  • inspecting the implicated venue.

If there is enough evidence implicating a food premises within the Borough as a possible source of the outbreak, we may decide to carry out a food hygiene inspection and if necessary close the business until we are satisfied the practices are safe.

If you believe that you are suffering from food poisoning (i.e. sickness and diarrhoea) please contact your GP or call NHS on 111.

For more information about infectious diseases and food poisoning or if you require information on how to prevent food poisoning in the home contact the Council's Environmental Health or look on the Public Health England  



Last updated: Wednesday 1st September 2021 07:59:48 AM
Review date: Thursday 16th December 2021 07:59:24 AM