E. coli enteritis is inflammation of the small intestine from Escherichia coli (E. coli) bacteria. It is the most common cause of travelers' diarrhea.

E. coli is a type of bacteria that normally lives in the intestines of humans and animals without causing any problems. However, certain types (or strains) of E. coli can cause food poisoning. One strain (E. coli O157:H7) can cause a severe case of food poisoning.

E. coli germs can get into the food you eat (called contamination) in different ways:

• Meat or poultry can come into contact with the normal bacteria from the intestines of an animal while it is being processed
• Water used during growing or shipping can contain manure or human waste
• Unsafe food handling or preparation in grocery stores, restaurants, or homes

Food poisoning can then occur from eating or drinking:

• Any food prepared by someone who did not use proper hand washing techniques
• Any food prepared using cooking utensils, cutting boards, and other tools that were not fully cleaned
• Dairy products or food containing mayonnaise (such as coleslaw or potato salad) that have sat out of the refrigerator too long. This is most likely to occur in cafeterias, on picnics, and during large social functions.
• Frozen or refrigerated foods that are not stored at the proper temperature or are not reheated properly
• Raw fish or oysters
• Raw fruits or vegetables that have not been washed well
• Raw vegetable or fruit juices and dairy (look for the word "pasteurized")
• Undercooked meats or eggs
• Water from a well or stream, or city or town water that has not been treated

Although not common, E. coli can be spread from one person to another. This may happen when someone does not wash their hands after a bowel movement and then touches other objects or someone else's hands.