CHROMOGENIC COLIFORM AGAR PLATE

Chromogenic Coliform Agar Plate is a chromogenic culture medium for the detection, enumeration and differentiation of coliform bacteria especially members of the Enterobacteriaceae family. The test is designed to detect coliform contamination by identifying enzyme activity related to lactose fermentation and characteristic colony colours, for microbiological quality testing of water and food samples.
The medium contains casein enzymatic hydrolysate, yeast extract, sorbitol and sodium pyruvate, which are sources of carbon, nitrogen, fermentable carbohydrate and other nutrients for microbial growth. The pH is buffered by disodium hydrogen phosphate and sodium dihydrogen phosphate, and the osmotic balance is maintained by sodium chloride. L-tryptophan increases the indole reaction and differentiation of Escherichia coli from other coliforms. Tergitol-7 enhances selectivity by reducing Gram-positive bacteria.
The formulation contains two chromogenic substrates, salmon-β-D-galactoside and X-glucuronide. Through the action of β-D-galactosidase coliforms turn salmon to red colonies and E. coli further cleaves both chromogens by the activities of β-D-galactosidase and β-D-glucuronidase and forms characteristic blue-violet colonies. IPTG enhances β-D-galactosidase expression, further supporting clear differentiation.

Enables rapid detection and differentiation of coliforms, particularly E. coli, through characteristic colony colours based on specific enzyme activities.