Chromogenic Coliforms Agar 500g Condalab 2080

Chromogenic Coliforms Agar is used for the detection of E. coli and other coliforms in water and food. The recovery and enumeration of Escherichia coli and coliforms is an important indicator in environmental and food hygiene. Ingredients such as peptone, sorbitol, and pyruvate grands quick colony, including infectious coliforms, and it permits the rocovery of sublethal thermally injured coliforms in the medium.

Tergitol-7 inhibits Gram-positive bacteria and some Gram-negative without affecting
the coliform bacteria and sodium chloride maintains the osmotic balance. The phosphate salts act as a buffer system and the bacteriological agar is the solidifying
agent.

Detection of ß-glucuronidase is widely used to differentiate Escherichia coli, as the enzyme is present in E. coli but not in other member of coliform group. The chromogenic mixture contains chromogenic substrates: Salmon-GAL and X-glucuronide. Coliform enzymes produced, ß-D-galactosidase and ß-D-glucuronidase, cleave these substrates resulting in the different coloration of bacteria colonies. The ß-D-galactosidase cleaves Salmon-GAL substrate, and gives a salmon-red color to the coliform colonies.

The ß-D-glucuronidase, enzyme characteristic of E. coli, cleaves X-glucuronide, giving a
blue color to these colonies. E. coli has the two enzymes and cleaves both chromogenic substances giving dark blue to violet colonies. Total coliforms are the sum of E. coli colonies plus salmon-red colonies. The addition of tryptophan to the medium allows the performance of the Indole test for further E. coli confirmation.