Mechanically tenderized beef caused at least five E. coli O157:H7 outbreaks between 2003 and 2009, causing 174 illnesses, four of them fatal, according to the national Centers for Disease Control and Prevention. The first documented outbreak in 2003 was traced to blade-tenderized, marinade-injected frozen filet mignon steaks consumers cooked at home, resulting in 13 illnesses that landed seven people in the hospital and killed three. A 2009 outbreak sickened 25 people, killing one and hospitalizing nine who had eaten mechanically tenderized sirloin served in restaurants. …