Food poisoning is the result of eating organisms or toxins in contaminated food. Most cases of food poisoning are from common bacteria such as 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.

Food poisoning tends to occur at picnics, school cafeterias, and large social functions. In these cases, food may be left out of the refrigerator too long or food preparation techniques may not be clean. Food poisoning often occurs from eating undercooked meats, dairy products, or food containing mayonnaise (like coleslaw or potato salad) that have sat out of the refrigerator too long.

Food poisoning can be caused by:

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

Botulism is a very serious form of food poisoning that can be fatal. It can come from improper home canning.

Infants and elderly people have the greatest risk for food poisoning. You are also at higher risk if:

• You have a serious medical condition, such as kidney disease or diabetes
• You have a weakened immune system
• 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 to avoid food poisoning.

The symptoms from the most common types of food poisoning generally start within 2 - 6 hours of eating the food. That time may be longer (even a number of days) or shorter, depending on the cause of the food poisoning.

Possible symptoms include:

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

Your health care provider will examine you for signs of food poisoning, such as tenderness in the abdomen and dehydration. Your provider will also ask about foods you have eaten recently.

Tests to find the cause may be done on your:

• Blood
• Leftover food
• Stool
• Vomit

Even if you have food poisoning, however, these tests may not be able to prove it.

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

• A thin, tube-like tool placed in the anus to look for the source of bleeding or infection (sigmoidoscopy)
• A test to measure electric impulses in the muscles (electromyography) to check for botulism
• A test of fluid from the spine (lumbar puncture) if you have signs of a nervous system disorder