Brilliance™ E. coli/Coliform Medium (Dehydrated)

Differentiate Escherichia coli and other coliform organisms in cultures produced from food and environmental samples with chromogenic Thermo Scientific™ Brilliance™ E. coli/Coliform Medium (Dehydrated). The medium uses two chromogens to differentiate between Escherichia coli and other coliforms. This results in purple E. coli colonies, as they are able to cleave both chromogens, while other coliforms produce pink colonies as they are only able to cleave the galactosidase chromogen.

The recovery and enumeration of Escherichia coli and coliforms present in environmental or food samples are important indicators of hygiene. Brilliance E. coli / Coliform Medium contains two chromogenic agents:

• Rose-Gal: detects ß-galactosidase activity
• X-Glu: detects ß-glucuronidase activity

Detection of ß-glucuronidase activity is widely used to differentiate E. coli, as this is present in E. coli but not in other members of the coliform group. As most coliforms are lactose-positive, ß -galactosidase activity, encoded by the lacZ gene, is then used to differentiate this group from other organisms able to grow on the selective medium. E. coli are able to cleave both chromogens resulting in purple colonies, while other coliforms are only able to cleave the galactoside chromogen, resulting in pink colonies.