ABSTRACT
Enterohemorrhagic Escherichia coli O157: H7 is one of the most important causes of bloody diarrhea. This bacterium is able to make bloody diarrhea or Hemorrhagic Colitis [HC] through verotoxin or shigatoxin production, and in acute forms it may lead to Hemolytic Uremic Syndrome [HUS] or Thrombotic Thrombocytopenic Purpurea [TTP]. Contamination with E. coli O157:H7 usually happens after consumption of animal products especially undercooked meats. The most important reservoir of this bacterium is beef and consumption of undercooked ground beef, especially in children younger than 10 years old, is the most common reason of food infection by this bacterium. Two important biochemical characteristics for detection of E. coli O157: H7 are lack of sorbitol fermentation and absence of glucuronidase. In order to control food infection with this bacterium, foods must be cooked thoroughly until reaching the temperature of at least 68.3°C, in the center