September 7, 2001. In addition to soliciting public input, FSIS asked the Institute of Medicine (IOM) to convene a committee of experts to review the draft and offer recommendations and suggestions for consideration as the agency finalizes the document. This report presents the results of that review.

E. coli O157:H7

E. coli serotype O157:H7 is a rare variety of E. coli, a normal inhabitant of the intestines of all animals, including humans (FDA, 2002). The pathogen produces large quantities of one or more related potent toxins, called Shiga toxins, that cause severe damage to the lining of the intestine and to other target organs, such as the kidneys. E. coli O157:H7 was first recognized as a cause of illness in 1982 during an outbreak of severe bloody diarrhea that was later traced to contaminated hamburgers (CDC, 1982). It has since been implicated in a number of outbreaks of intestinal distress. The most severe outcome in the general population is typically hemorrhagic colitis, a prominent symptom of which is bloody diarrhea. Life-threatening complications, however, sometimes ensue. Some victims, particularly the very young, may develop hemolytic uremic syndrome (HUS). HUS, which is characterized by renal failure and hemolytic anemia, occurs in up to 15% of hemorrhagic colitis victims and can lead to permanent loss of kidney function. In the elderly, the combination of HUS with fever and neurologic dysfunction is characteristic of thrombotic thrombocytopenic purpura (TTP). Left untreated, TTP has a mortality of about 95%; however, early diagnosis and treatment yield a survival rate of 80–90% (Abumuhor and Kearns, 2002). Overall, the Centers for Disease Control and Prevention estimates that E. coli O157:H7 is responsible for some 73,500 cases of infection, 2,150 hospitalizations, and 61 deaths in the United States each year (Mead et al., 1999).

Eating meat, particularly ground beef, that has not been cooked sufficiently to kill E. coli O157:H7 is thought to be the primary cause of infection. Cross contamination—which occurs when harmful bacteria in raw beef or its juices are spread to other foods through contact with cutting boards, utensils, and the like—also accounts for illnesses. Among other known sources of infection are consumption of contaminated sprouts, lettuce, salami, and unpasteurized milk and fruit juice; swimming in or drinking contaminated water; and contact with the stools of infected animals or people. FSIS has classified E. coli O157:H7 as an adulterant in raw ground beef, thus banning the sale of any ground beef contaminated with it.3

3  

Under the Federal Meat Inspection Act, meat is adulterated if it bears or contains any poisonous or deleterious substance, which might render it injurious to health. E. coli O157:H7 has been classified as an adulterant in raw ground beef since 1994.



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