Escherichia coli (E coli)

E coli is a normal inhabitant of animal and human intestines where it suppresses the growth of harmful bacteria and synthesises vitamins.

It is usually used as an indicator of faecal contamination of food or water. Certain strains are known to be pathogenic and produce an enterotoxin in the intestine which causes food poisoning.

One group is responsible for severe infantile diarrhoea and another group causes travellers diarrhoea.

A rare group which produces a potent toxin is E coli 0157, severe damage to the lining of the intestine can occur.

Outbreaks of food poisoning due to this group have been associated with raw, undercooked minced beef products or unpasteurised milk. Some victims, particularly the elderly or very young, have developed anaemia and renal failure. The illness can have a mortality rate as high as 50% in the elderly.

Control:

Ensure all meat is cooked until the juices run clear and a centre temperature of 75 deg C is achieved. Avoid unpasteurised milk. Separate raw and cooked foods to prevent cross contamination. Disinfect all surfaces and utensils used for food preparation. Wash hands regularly and use a bactericide.

Foods incriminated:

The organism has on occasions been isolated from soft cheeses but more likely is contamination from infected food handlers.

Target populations:

All people are susceptible to E coli but special care must be taken in residential care environments.