for presumptive identification of Escherichia coli and other coliforms.
CHROMOGENIC ECC AGAR is used for presumptive identification of Escherichia coli and other coliforms. This medium contains Peptone, special and Yeast extracts carbon, nitrogen and growth nutrients. Chromogenic mixture contains two Chromogens as X-glucuronide and Salmon-GAL. Xglucuronide is cleaved by the enzyme β-glucuronidase produced by Escherichia coli. Salmon-GAL is cleaved by the enzyme galactosidase produced by a majority of coliforms, including Escherichia coli. Lactose is the fermentable carbohydrate, which helps in detecting lactose fermenters with Neutral red as an indicator. Disodium hydrogen phosphate and Potassium dihydrogen phosphate are the buffering agents. Sodium chloride maintains the osmotic equilibrium in the medium. Note: Incomplete agar melting during preparation will invariably lead to significant inconsistency in the gel strength of the solidified agar, after sterilization and cooling. Prior to inoculate, the prepared media should be brought to room temperature. Directly, inoculate plate as soon as possible with specimen and streak for isolation. Count the blue/purple colonies and multiply by the dilution factor.