Tryptone Bile X-glucuronide agar 500g

Chromocult^® Tryptone Bile X-glucuronide agar is a selective medium for the enumeration of Escherichia coli. The presence of the enzyme β-D-glucuronidase differentiates most E. coli from other coliforms. E. coli absorbs the chromogenic substrate 5-bromo-4-chloro-3- indolyl-β-D-glucuronide (X-β-D-glucuronide) while, the enzyme β-glucuronidase splits the bond between the chromophore 5-bromo-4-chloro-3-indolyl and the β-D-glucuronide. The formed E. coli colonies are colored blue to blue green. The growth of accompanying Gram-positive flora is largely inhibited due to the presence of bile salts and the high incubation temperature of 44°C. Some E. coli (3-4 %) are β-D-glucuronidase negative and appear as colorless colonies (e.g. most E. coli O157 strains) or do not grow at the elevated temperature of 44°C (e.g. E. coli 0157:H7).

Chromocult^® Tryptone Bile X-glucuronide agar is used for the enumeration, detection, and identification of β-glucuronidase positive Escherichia coli from food and feeding stuff, as well as from environmental samples in the area of food production and food handling.