A reader of the Suburban Chicago News Web site asks, "There has been a lot in the news about E. coli in food lately. What is it? How do I know if I have consumed a food product that is infected with E. coli?"

E. coli is a common type of bacteria. It is short for the medical term Escherichia coli, which normally lives inside our intestines, where it helps the body break down and digest the food we eat. Most of the hundreds of types, or strains, of E. coli live harmlessly in the digestive tracts of humans and animals.

There are some strains however that produce a powerful toxin that causes bloody diarrhea and occasionally can cause severe blood problems and kidney failure, called hemolytic uremic syndrome.