Food poisoning
Food poisoning is an acute illness which usually occurs within 1 to 36 hours of consuming contaminated or poisonous food. Food poisoning symptoms include vomiting, diarrhoea, abdominal pain, nausea and fever and normally last between 1 and 7 days. The period between eating the affected food and the start of symptoms is called the Incubation Period.
Causes of food poisoning
Food poisoning may be caused by a variety of sources including:
- bacteria
- viruses
- chemicals
- metals
- poisonous plants/animals.
Food poisoning commonly occurs when:
- high risk food is contaminated
- bacteria multiply in the food
- bacteria survive within the food.
Bacteria are the most common cause of food poisoning. Bacteria can multiply in food and usually a large number of bacteria are required to make people ill.
Viruses do not multiply in food but a smaller number are required to cause illness. Airborne infection is common and can spread easily from person to person.
Chemical food poisoning is rare and usually results from accidental ingestion of poisonous chemicals.
Metals can cause food poisoning; if food becomes contaminated with metals such as lead and mercury and is ingested it can cause illness.
Poisonous plants and animals such as Japanese Puffer Fish, Deadly Nightshade and certain toadstools can cause illness when ingested.
Food poisoning symptoms
| Agent | Source | Incubation period | Symptoms & usual duration |
| Salmonella | Raw meat, poultry, eggs, unpasteurised milk, pets, terrapins, infected food handlers. | 6-72 hours; usually 12-36 hours | Diarrhoea, vomiting, fever, abdominal pain 1-5 days |
| Campylobacter | Raw meat, poultry, raw/bird pecked milk, untreated water, pets. | 1-11 days; usually 2-5 days | Abdominal pain, diarrhoea 2-5 days |
Listeria Monomctogenes | Found in environment, cattle, sheep, silage, unpasteurised milk products including soft cheeses, pates. | Variable; usually 4-21 days | Fever, affects central nervous system Variable |
Staphylococcus aureus | Human nose, mouth, cuts and wounds. | 1-7 hours; usually 2-4 hours | Vomiting, abdominal pain, diarrhoea, fainting 6-24 hours |
Clostridium Perfringens | Faeces of animal and man, soil (on vegetable), dust, sewage. | 8-22 hours; usually 12-18 hours | Diarrhoea, abdominal pain 12-48 hours |
Bacillus cereus (toxin in food) | Cereal products, especially rice, spices, dust, soil. | 1-5 hours | Vomiting, abdominal pain, some diarrhoea 1-2 days |
Bacillus cereus (toxin in gut) | Cereal products, especially rice, spices, dust, soil. | 8-16 hours | Diarrhoea, abdominal pain, some vomiting 1-2 days |
Vibrio Paraheamolyticus | Sea water, shellfish. | 2-48 hours; usually 10-18 hours | Diarrhoea, abdominal pain, some vomiting 2-5 days |
| Escherichia coli (infective) | Aminal origins – cattle, sheep, humans, sewage, meat & raw milk. | 12-72 hours; usually 12-24 hours | Diarrhoea, abdominal pain, fever 2-3 days |
| Clostridium botulinum | Soil, meat, fish and vegetables | 8 hours to 8 days; usually 12-36 hours | Central nervous system (difficulty breathing, double vision, nerve paralysis), diarrhoea, vomiting Variable can be fatal |
| Chemicals (e.g. metallic poisons, pesticides, etc) | Less than 1 hours | Vomiting, abdominal pain, possibly effects on central nervous system | |
| Poisonous plants/animals | Less than 15 hours | Vomiting, abdominal pain, possibly effects on central nervous system | |
| Norwalk Virus | 24-48 hours | Vomiting, diarrhoea, abdominal pain |
Preventing food poisoning
The three basic steps to prevent food poisoning are:
- Preventing contamination of food
- Preventing multiplication of bacteria
- Destroying bacteria
Preventing contamination
- purchase food from reputable suppliers
- maintain good hygiene standards
- minimise handling
- separate raw and cooked food, surfaces & equipment
- cover food
- ensure waste is stored and disposed of properly
- effectively clean and disinfect all surfaces.
Preventing multiplication
- keep food either below 5ºC or above 63ºC
- cool food quickly and cover it
- Don’t leave food at room temperature.
Destroying bacteria
- thoroughly cooking (to 75ºC at core of food)
Reporting food poisoning
If you suspect you are suffering from food poisoning you should consult medical advice. Maintaining good personal hygiene is paramount; you must thoroughly wash your hands after using the toilet and before handling food.
People in occupations, such as nurses, food handlers and people who work with the young or elderly must not go to work if they have food poisoning as there is a possibility that they may spread the infection.
If you have any concerns that you may have contracted food poisoning from eating food at or from an establishment in the Borough of Walsall please contact this Division on 01922 652217 and an Officer will carry out an appropriate investigation.
Contact us
Public Protection Services
Environmental Health Division
Challenge Building
Hatherton Road
Walsall
WS1 1DJ
Telephone 01922 652210
Email foodsafety@walsall.gov.uk
This page was last updated on 12 May 2008