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What is food poisoning?

Food-borne illnesses affect millions of Americans each year. Many people who think they have the "stomach flu" or a virus are really victims of a mild case of food poisoning, caused by bacteria and viruses found in food.


Most cases of food poisoning mimic gastroenteritis, and many people with mild cases of food poisoning think they have the "stomach flu." However, the onset of symptoms is usually very sudden and abrupt, often within hours of eating the contaminated food. The following are the most common symptoms of food poisoning:

  • Abdominal cramps
  • Watery and/or bloody diarrhea
  • Nausea and vomiting
  • Headache
  • Fever
  • Abdominal distention and gas

When to see a doctor

The symptoms of food poisoning may resemble other medical conditions or problems. Always consult your doctor for a diagnosis. Be sure to see your doctor right away if you're unable to keep fluids down or your symptoms are persistent. 

Note that certain individuals are particularly vulnerable to food poisoning and should seek immediate medical attention. This includes young children, the elderly, pregnant women (because of the risk to the fetus) and people with chronic or serious illnesses, whose immune systems are already weakened.


Most food-borne illnesses are caused by eating food containing certain types of bacteria or viruses. After a person has eaten these foods, the microorganisms continue to grow in the digestive tract, causing an infection. Foods can also cause illness if they contain a toxin or poison produced by bacteria growing in food.

Several different kinds of bacteria can cause food poisoning. Some of the common bacteria include the following:

  • Salmonella and campylobacter: Normally found in warm-blooded animals, such as poultry and reptiles. Also may be present in raw meat, poultry, eggs or unpasteurized dairy products.
  • Clostridium perfringens: May be present in raw meat, poultry, eggs or unpasteurized dairy products, as well as in vegetables and crops that come into contact with soil. Infection may occur when soups, stew, and gravies made with meat, fish or poultry are stored improperly or left unrefrigerated for several hours
  • Listeria: Mainly associated with raw foods of animal origins, including unpasteurized cheese and milk.
  • Staphylococci: Occur normally on human skin and in the nose and throat and may be transmitted to food when handled by someone with the bacterium.
  • Escherichia coli (E. coli): Found in the intestines of healthy cattle and transmitted through undercooked beef (especially ground beef) or unpasteurized milk
  • Clostridium botulinum: This bacteria can cause botulism, a rare but deadly form of food poisoning. Clostridium botulinum is found almost everywhere, including in soil and water. Low acid foods (such as meat, fish, poultry or vegetables) that are improperly canned or improperly preserved may be breeding grounds for this bacteria. Raw honey and corn syrup can also cause botulism in infants. Babies under the age of one year old should never be given honey or corn syrup for this reason.

In addition, hepatitis A and other viral diseases may be passed through the hands of infected people onto the hands of food handlers or into sewage. Shellfish and other foods which may have been exposed to sewage-contaminated water can transmit these viral diseases.

Types of treatment

Most mild cases of food poisoning are often treated as gastroenteritis, with fluid replacement and control of nausea and vomiting being the primary focus. Antibiotics may actually make the situation worse. In serious cases of food poisoning, hospitalization may be necessary


Here are some ways you can help prevent food poisoning: Thoroughly wash hands before handling food.

  • Wash hands after using the toilet, changing diapers, smoking, blowing your nose, coughing or sneezing.
  • Wash hands after touching raw meat, seafood, poultry or eggs and before working with any other foods.
  • Do not use wooden cutting boards for cutting raw fish, poultry or meat. Plastic boards are easier to sanitize.
  • Thoroughly clean any surface or utensil after each use.
  • Cook poultry, beef and eggs thoroughly before eating.
  • Do not eat or drink foods made from raw or undercooked eggs, poultry, meat or unpasteurized milk, or other dairy products made from unpasteurized milk.
  • Wash all produce thoroughly before eating.
  • Avoid cross-contamination of foods by keeping produce, cooked foods and ready-to-eat foods separate from uncooked meats and raw eggs.
  • Do not leave mayonnaise, salad dressings or foods containing either of these items unrefrigerated for extended periods.
  • If you're unsure about how long a food has been left unrefrigerated or about whether or not it has spoiled, don't take your chances. When in doubt, throw it out.
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