Food poisoning is the result of eating organisms or toxins in contaminated food. Most cases of food poisoning are from common bacteria like Staphylococcus or E. coli.

Food poisoning can affect one person or it can occur as an outbreak in a group of people who all ate the same contaminated food.

Even though food poisoning is relatively rare in the United States, it affects between 60 and 80 million people worldwide each year and results in approximately 6 to 8 million deaths.

Food poisoning tends to occur at picnics, school cafeterias, and large social functions. These are situations where food may be left unrefrigerated too long or food preparation techniques are not clean. Food poisoning often occurs from eating undercooked meats, dairy products, or food containing mayonaise (like coleslaw or potato salad) that have sat out too long.

Food poisoning can be caused by:

• Staph aureus
• E. coli enteritis
• Salmonella
• Shigella
• Campylobacter
• Cholera
• Botulism
• Mushroom poisoning
• Listeria
• Bacillus cereus
• Fish poisoning
• Yersinia

Infants and elderly people have the greatest risk for food poisoning. You are also at higher risk if you have a serious medical condition, like kidney disease or diabetes, a weakened immune system, or you travel outside of the U.S. to areas where there is more exposure to organisms that cause food poisoning. Pregnant and breastfeeding women have to be especially careful.

The symptoms from the most common types of food poisoning generally start within 2 to 6 hours of eating the food responsible. That time may be longer (even a number of days) or shorter, depending on the toxin or organism responsible for the food poisoning. The possible symptoms include:

• Nausea and vomiting
• Abdominal cramps
• Diarrhea (may be bloody)
• Fever and chills
• Weakness (may be serious and lead to respiratory arrest, as in the case of botulism)
• Headache

Your healthcare provider will examine you for signs and symptoms of food poisoning, such as stomach problems and dehydration. Your provider will also ask about foods you have eaten recently. Tests of your vomit, blood, stool, and any leftover food may identify the cause. Even if you have food poisoning, however, these tests may not be able to verify it.

In rare but possibly serious cases, your doctor may order one or more of the following procedures:

• Sigmoidoscopy (putting a thin, tube-like tool into the anus) to look for the source of bleeding or infection if these symptoms do not go away and the cause has not been found.
• Electromyography (a test to measure electric impulses in the muscles) to check for botulism.
• Lumbar puncture (a test of fluid from the spine) if you have signs of a nervous system disorder.