E. coli are bacteria that normally live in the intestines of humans and animals. Although most strains of this bacteria are harmless, several are known to produce toxins that can cause diarrhea.
Infection is caused by eating food containing the bacteria.
The bacteria live in the intestines of some healthy cattle, and contamination of the meat may occur in the slaughtering process. Eating meat that is rare or inadequately cooked is the most common way of getting the infection. Some infected people may have mild diarrhea or no symptoms at all. Most identified cases develop severe diarrhea and abdominal cramps. Blood is often seen in the stool.