for simultaneous detection of total coliforms and Escherichia coli in water and foods. TM Media is the best brand of chromogenic coliform agar with sls and Titan Media is best place to buy chromogenic coliform in India.
CHROMOGENIC COLIFORM AGAR W/SLS is used for simultaneous detection of total coliforms and Escherichia coli in water. The differentiation between Coliforms and E. coli is given by the presence of Chromogenic mixture Salmon-GAL, a chromogenic substrate for the detection of β-galactosidase and X-GLUC, a chromogen substrate for the detection of β- glucuronidase. Salmon-GAL is hydrolysed by coliforms releasing a salmon colour pigment; this reaction is strengthened in the medium by the presence of IPTG (isopropil-β-D-thiogalactopiranoside). X-GLUC is hydrolysed, among Enterobacteria, by E. coli, and by a few other strains of Salmonella and Shigella releasing a blue pigment. However, in the presence of the two substrates, and cleavage of these by E.coli results in the formation of dark blue to violet colonies. The presence of Tryptophan in the medium allows testing the indole directly onto the colonies by adding Kovac’s Reagent, for the confirmation of E. coli. Medium contains special Peptone provides essential nutrients for growth like nitrogen, vitamins, minerals and amino acids. The combined action of Peptone and Sodium pyruvate allow rapid colony growth in this phosphate buffered medium, which also allows easy recovery of sub lethally, thermally injured, Coliforms. Sodium chloride provides the osmotic environment necessary for growth. Agar acts as the solidifying agent