E. coli is one of the most common causes of foodborne illness. E. coli, short for Escherichia coli, is a bacterium from the family Enterobacteriaceae usually found in the digestive system of healthy humans and animals. There are hundreds of known E. coli strains, with E. coli O157:H7 and other shiga-toxin producing strains being the most dangerous. This enterohemorrhagic strain (causing bloody diarrhea and colitis) is responsible for an estimated 73,000 cases of infection and 61 deaths in the US annually. E. coli is found everywhere in the environment, but mostly occupies animal surfaces and digestive systems. It is transmitted through fecal contamination, which means foods that may have contacted animals or animal or human wastes should be washed and/or cooked thoroughly before being consumed.
E. coli O157:H7 is a Gram-negative rod-shaped bacterium that produces potent toxins. These toxins cause severe damage to the intestinal tract lining of those infected with the bacteria. The presence of E. coli O157:H7 toxins is responsible for the symptoms associated with infection: hemorrhagic colitis, hemolytic uremic syndrome (HUS) and even death. The organism can survive at low temperatures and under acidic conditions, making it difficult to eradicate in nature.
An acute disease associated with this organism is named hemorrhagic colitis. The symptoms characteristic of this disease are watery and/or bloody diarrhea, fever, nausea, severe abdominal cramping and vomiting. Because most people recover from this infection on their own, treatment is usually not necessary. Symptoms can appear within hours or up to several days after ingestion of the bacteria (10-100 cells) and the illness duration is normally 5-10 days. Some individuals may develop hemolytic uremic syndrome (HUS). In the very young, this disorder can cause renal failure, hemolytic anemia, permanent loss of kidney function and even death. In the elderly, these symptoms as well as thrombotic thrombocytopenic purpura (HUS with additional neurological dysfunction and/or fever) may occur.
E. coli O157:H7 can infect anyone but is more prone to attacking the very young (under 5 years) and the very old. This infection is also associated with immuno-compromised patients. Those working in slaughterhouses, farms, hospitals, nursing homes, nursery schools, and food preparation locations have greater exposure than the rest of the population.
The most common sources of E. coli O157:H7 infections are raw or undercooked hamburger, other meat, game meat, alfalfa sprouts, unpasteurized fruit juices, dry-cured salami, lettuce, cheese curds, unpasteurized or raw milk, contaminated water or ice and person-to-person transmission. Fruits and vegetables can also cause infection due to contact with contaminated water. However, infection is most often due to consumption of undercooked or raw meats. There appears to be a very low infective dose for this organism (10-100 cells), making adequate sanitation and/or proper processing of foods critically important.
The suggestions below are good examples of how to improve and prevent infections www.fmi.org:
Because illness is associated with E. coli O157:H7, handwashing must be thorough. It is important to wash hands before, during and after: handling raw foods, smoking, changing diapers, cleaning, using the restroom and touching soiled equipment or clothing. This is the proper technique for hand washing: