Colorado State University Extension
SafeFood Rapid Response Network
SAFEFOOD NEWS - Fall 1997 - Vol 2 no 1
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E. Coli 0157:H7 Harbinger of Change for Food Safety
Never underestimate the power of a single-celled organism. One small bacterium, Escherichia coli 0157:H7, is forcing us to rethink and change many of the ways we enjoy, handle, and think about our food supply.
During the last two weeks in August of this year, this pathogen was at the root of one of the largest food recalls in history. It has captured the attention of the national news media and has reopened the public debate on the use of irradiation to reduce pathogens in food.
And, it is not alone. E. coli 0157:H7 is only one of a number of different strains of E. coli that produce a shigella-like toxin that's highly infectious.
This particular strain attaches itself to the intestinal wall of its victims and releases a toxin that causes severe abdominal cramps, bloody diarrhea and vomiting that lasts a week or longer. In small children and the elderly it can progress to kidney failure.
First reported in 1982, most outbreaks of illness from E. coli 0157:H7 have been traced to undercooked ground beef, raw milk, unpasteurized apple juice and contaminated water. As in one case in Washington State, the disease can be passed between children through poor hygiene and diapering practices.
While there are a number of different bacteria that find their way into food and cause illness, the characteristics that make this particular pathogen more significant than other pathogens are its low infectious dose, its unusual acid and cold tolerances, and its potential for severe consequences among all age groups. Unlike many foodborne pathogens which need to number in the thousands before they cause problems for humans, less than ten E. coli 0157:H7 cells have been known to cause foodborne illness in people. Further, three methods commonly used to prevent growth of bacteria -- refrigeration, increasing the acidity, and reducing the water activity level -- don't seem to help. While other pathogens wilt and die, E. coli 0157:H7 has been known to survive for weeks to months on dried jerky and in such acidic foods as fermented sausage and apple cider. Adding insult to injury, the survival time in these foods is greatly extended at refrigeration temperatures (32 to 40 degrees F) compared to storage at room temperature.
What this means in practical terms is that it's not enough to reduce the level of contamination or prevent further growth as is the case for most bacteria of concern. Rather, E. coli 0157:H7 must be destroyed to insure safety in susceptible persons.
Given the complexities of the issues surrounding E. coli 0157:H7, we felt it appropriate to devote this issue of SafeFood News to news and views regarding the current war on this bug.
Source: IFT Status Summary, E. coli 0157:H7, Vol. 51, No. 10, Oct. 1997.
Updated Monday, August 29, 2011
