For the simultaneous detection and enumeration of E.coli and other coliforms
in water samples.
Broth Technique Product
Typical Appearance of microrganisms
E.coli → blue
Other faecal coliform bacteria → purple
Other gram negative bacteria → colourless or inhibited
Strict regulations exist for E. coli/coliform presence in water 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 and numerating E. coli and coliforms.
Coliforms, Enterobacteriacae able to ferment lactose, are bacteria present in human and warm-blooded animal intestinal flora, in the soil and water. Coliforms are proof of organic, environmental or faecal contamination. Faecal contamination, due to colifoms coming from animal waste, consists mainly of Escherichia coli and thermotolerant Klebsiella.
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. High contamination may lead to suspension of the water supply and food recall by supermarkets.
In the U.S.A. the EPA recommendations through the Total Coliform Rule (TRC) are:
• <1 000 CFU/100 mL for a fishing and boating water quality.
• <100 CFU/100 mL for a body-contact recreation water quality.
• <1 CFU/100 mL for a drinking water quality.
1. Simplicity: Very easy to prepare compared to agar based culture media.
2. Economic: only 2 mL/test (instead of the 10-20 mL for the other culture media).