Escherichia coli 0157H7 179

Annually the CDC estimates that E. coli alone is responsible for 20,000 cases of food poisoning, although these estimates may not be accurate since physicians are not required to report these poisonings.

A study by the Western States Meats Association found that E. coli was present in 1.5 percent of ground pork and also in poultry, and 3.7 percent in beef. In the past, people got E. coli food poisoning by drinking tap water in foreign countries. In the wake of the mass poisonings and deaths from E. coli poisoning, the government vowed to revamp the federal meat inspection system, which relied on visual inspections. In related action, the United States Dairy Association (USDA) decided to issue new labels for raw meat and poultry that discuss safe handling and cooking methods.

The Shiga gene has continued to spread and has now been found in other strains of E. coli, as well as other bacteria common to the human intestine, such as enterobacter.

Figures from the Centers for Disease Control suggest there may be 20,000 illnesses a year in this country, with 250 to 500 deaths from E. coli 0157:H7 alone. According to experts at the Food-borne Diseases Epidemiology Section of the federal centers, an additional 10,000 to 20,000 cases of food poisoning may be caused by Shiga toxin from other strains of bacteria for a total of perhaps 40,000 cases in the United States. This is part of an estimated total of about seven million cases of food-borne illness in general.

Recent epidemics have included the November 1996 cases involving a 15-month-old Colorado child who died after drinking tainted unpasteur-ized odwalla apple juice; another 50 people became sick. In the summer of 1996 a similar epidemic swept Japan, killing seven people and infecting almost 9,000 Japanese. In the biggest outbreak, 6,500 people came down with E. coli infection in Sakai; the infection was traced to city-supplied school lunches.

outbreaks have been traced to many different types of food. It has been found to survive in dry fermented meat despite production standards that meet federal and industry food processing requirements, scientists say. It has been found in salami, where the bacteria may have been present on raw meat that was brought into a plant and subsequently survived the fermentation and drying steps involved in salami production.

primarily, the organism is found in a small number of cattle farms, living in the intestines of healthy cattle. Meat becomes contaminated during slaughter, and organisms can be mixed with beef when it is ground in huge vats. Alternatively, bacteria on a cow's udders or on milking equipment can find its way into raw milk.

Since contaminated meat looks and smells normal, it is possible to eat tainted meat unknowingly. Although the number of organisms needed to cause disease is not known, it is believed to be very small.

The problem is not with steak; a bit of bacterial contamination on the surface of a steak is not much of a threat, because it is quickly killed when the meat hits the pan. It is the practice of grinding the meat that gives bacteria its chance. When a contaminated steak is minced up and mixed with other beef from other animals, the bacteria become widely distributed—not just on the surface but throughout the meat. Contaminated and under-cooked hamburger is suspected of causing more than half of all outbreaks of bloody diarrhea. Many outbreaks have begun in fast-food restaurants, but since the large chains have begun to sample their meat, the real problem today lies in grocery store hamburger, according to experts. The meat in grocery stores, the experts say, goes largely untested.

The toxin-making bacteria are killed only if the hamburger is cooked to an inside temperature of 155°F, hot enough to eliminate all meat pinkness.

Drinking unpasteurized milk, as well as swimming in or drinking sewage-contaminated water, also can cause infection.

The disease can also be transmitted from person to person through contact with contaminated stool, if hygiene or handwashing is not adequate. This is especially common in day care centers and among toddlers who are not yet toilet trained.


The E. coli 0157:H7 bacterium produces toxins that cause severe cramps and then watery or bloody diarrhea lasting for several days. other symptoms include nausea and vomiting appearing within hours to a week after eating, but not usually any fever. Most people recover quickly and completely, but the complications are what make this a serious disease.

In certain people at risk (such as among the very young or old), the bacteria may cause hemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the kidneys fail. Between two and seven percent of infections lead to this complication. In the United States HUS is the main cause of kidney failure in children; most cases are caused by infection with this type of E. coli.

Patients are infectious for about six days while bacteria are being excreted in the stool. There is no solid evidence, but it appears that victims can get this infection more than once.

Was this article helpful?

0 0

Post a comment