COMPASS ® cc Agar allows for the detection and enumeration of Escherichia coli and coliform bacteria in water by the method of membrane filtration in 24 hours and without additional step of confirmation by testing for oxidase or revelation of the production of indole from tryptophan. COMPASS ® cc Agar is suitable both for control of disinfected water and other drinking water comprising only a small number of bacteria, as control of water filled with interfering flora.
- The simultaneous presence of two chromogenic substrates for the detection of two specific enzyme activities: the β-galactosidase and β-glucuronidase.
- Bacteria belonging to the coliform group are characterized by the production of a β-galactosidase (β-gal). This enzyme reacts with the chromogen to form a mixture pink precipitate.
- All strains of Escherichia coli possess a β-galactosidase and 94 to 97% of them also possess a β-glucuronidase (GUD). The presence of this enzyme is revealed by the presence of a compound of blue color. The simultaneous action of two enzymes reveals colonies of Escherichia coli in blue violet.