What Is Escherichia coli (E. coli)?

Escherichia coli, usually abbreviated and called E. coli in short, is a type of bacteria in the genus Escherichia. It is normally found in the intestine of healthy people and warm-blooded animals. Most of the Escherichia coli bacteria strains are harmless, but some strains like O157: H7 and E. coli O104:H4 are a threat to human health. While healthy adults recover from the infection in a week, young children, older adults and immunocompromised people are more vulnerable and may develop serious complications. An outbreak of E. coli infection in 2000, in Walkerton, Ontario, killed seven people and more than 2,300 others fell in ill. The Walkerton E. coli outbreak occurred when Escherichia coli bacteria contaminated the water supply of the small community of Walkerton. Health authorities in Canada normally deal with a few thousand cases of E. coli illness a year.

E. coli infections are generally caused by contaminated food or water and it can also be easily spread from person to person. E. coli are mostly found in improperly cooked meat, raw fruits, uncooked vegetables including sprouts, untreated drinking water, unpasteurized (raw) milk or (raw) milk products, unpasteurized apple juice/cider, and direct contact with animals at petting zoos or farms.

Symptoms of Escherichia coli infections

Symptoms of E. coli infections start within 3 to 4 days after exposure. But the incubation period can be varied from 1 to 10 days. Symptoms can be characterised by severe abdominal cramping, nausea, vomiting and diarrhea, which may range from mild and watery to severe and bloody. Some people may show no symptoms at all but can still carry the bacteria and pass it on to people.
In most cases, healthy adults recover from the E.coli illness within five to 10 days. In a small number of cases, E. coli contamination can lead to hemolytic uremic syndrome (HUS), a life-threatening condition that is treated in intensive care units.

How to prevent Escherichia coli infections

Proper hygiene, safe food handling and preparation practices are important in preventing the spread of E. coli. It is also a good idea to keep pets away from food storage and preparation areas.

Testing for Escherichia coli

The presence of E. coli in food or water is accepted as indicative of recent fecal contamination and the possible presence of frank pathogens. Although the concept of using E. coli as an indirect indicator of health risk is sound, it is complicated in practice, due to the presence of other enteric bacteria like Citrobacter, Klebsiella and Enterobacter that are similar to E. coli. As a result, the term “coliform” is used to describe this group of enteric bacteria.

Testing for coliforms is used to determine the sanitary quality of water or as a general indicator of sanitary condition in the food-processing environment. Fecal coliforms remain the standard indicator of choice for shellfish and shellfish harvest waters; and Escherichia coli is used to indicate recent fecal contamination or unsanitary processing.

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