Enumerate and differentiate coliforms and Escherichia coli in water samples with Thermo Scientific™ Oxoid™ Chromogenic Coliform Agar in accordance with ISO 9308-1 guidelines for water quality analysis. Target organisms are easy to differentiate, E.coli forming dark blue/violet colonies and coliforms pink to red colonies. Achieve complete detection within 24 hours, removing the need for subculturing.
Chromogenic Coliform Agar is a fast, accurate, and efficient way to detect coliforms and E.coli during microbiological quality testing of drinking water, disinfected pool water, and treatment plant samples. The guideline, ISO 9308-1:2014 Enumeration of Escherichia coli and coliform bacteria –Part 1: Membrane filtration method for waters with low bacterial background flora, specifies a method based on membrane filtration, subsequent culture on a Chromogenic Coliform Agar medium, and calculation of the number of target organisms in the sample.
Chromogenic Coliform Agar utilizes specific enzymes associated with general coliforms and E.coli for differentiation.
The chromogen Salmon GAL, when cleaved by D-galactosidase, produces a pink to red coloration; this coloration and enzyme are associated with coliforms.
E.coli contains D-galactosidase, which cleaves Salmon GAL; however, it also contains D-glucuronidase, which cleaves the chromogen X-glucuronide. The combination of these chromogens produces a dark blue to violet coloration associated with E.coli.
Tergitol-7 within the medium inhibits Gram positive bacteria and Gram negative bacteria with exception of coliforms.