Coliforms, Enterobacteriacae able to ferment lactose, are bacteria present in human and warm blooded animals intestinal flora, in the soil and water. Coliforms are indicators of organic, environmental or faecal contamination.

Strict regulations exist for E. coli/coliform abscence in water and food samples. This can be explained by the importance of these germs in determining water and food safety. Worldwide, water and food quality control for human consumption are based on detecting the presence/absence of E. coli and coliforms.

E. coli can contaminate drinking water when the water treatment system is inadequate or during periods of very high rainfalls. Monitoring of food and water production is essential. Contamination may lead to suspension of the water supply and food recall by supermarkets.