CHICAGO-The unusual and hardy characteristics of the pathogen Escherichia coli O157:H7 "have prompted food microbiologists to rewrite the rule book on food safety," according to the Institute of Food Technologists' (IFT's) October 1997 Scientific Status Summary "Foodborne Disease Significance of Escherichia coli O157:H7 and Other Enterohemorrhagic E. coli."
"E. coli O157:H7 is more significant than other well-recognized foodborne pathogens for reasons including the severe consequences of infection that affect all age groups, its low infectious dose, its unusual acid tolerance, and its apparent special but inexplicable association with ruminants [cattle, deer, and sheep] that are used for food," wrote Robert L. Buchanan, Ph.D., and Michael P. Doyle, Ph.D., the document's authors.
Less than ten E. coli O157:H7 cells may cause foodborne illness in people. Infectious doses associated with this pathogen in outbreaks have been consistently low?a characteristic associated with the organism's acid tolerance, according to Buchanan and Doyle.
Unlike most other pathogens, E. coli O157:H7 has been known to survive for several weeks to months in acidic foods such as fermented sausage and apple cider, and experimentally, in foods like mayonnaise and cheddar cheese. The survival time in these foods is greatly extended at refrigeration temperatures (32 F-40 F) as opposed to room temperature. Recent studies have also indicated that acid tolerance may increase the pathogen's resistance to other stresses such as heat, radiation, and antimicrobials.
"[E. coli O157:H7's] low infectious dose in combination with the disease severity means that successful prevention strategies must focus on reducing or eliminating the presence of the microorganism, rather than on preventing pathogen growth as is done in more traditional approaches," Buchanan and Doyle wrote.
The Hazard Analysis and Critical Control Point (HACCP) system can reduce the
risk of E. coli O157:H7 infec
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