Compass CC for E.coli & Coliforms (RTU)

COMPASS® cc Agar is certified NF VALIDATION for the enumeration of E. coli and coliforms in 24 ± 3 hours in water destined for human consumption. with respect to the reference method NF EN ISO 9308-1:2000. Please refer to the certificate available on the NF VALIDATION website for the validity end date of the method. In case of NF Validation mark, refer to ISO 8199 : 2018 for media preparation and enumeration.

The simultaneous presence of two chromogenic substrates allow the detection of two types of specific enzymatic activity: β-galactosidase and β-glucuronidase. Bacteria belonging to the group coliforms are distinguished by their production of a β-galactosidase (β-gal). This enzyme
reacts with the chromogenic substrate mixture to form a pink precipitate. All the strains of E. coli possess the β-galactosidase activity and 94 to 97% of them equally possess a β-glucuronidase (GUD) activity.

The presence of this second enzyme is revealed by the visualization of a blue color. The simultaneous action of the two enzymes give rise to purple colonies with Escherichia coli. In light of the principles used, the method reveals bacteria that are lactose negative but β-galactosidase positive.

The special mixture of peptones favors the excellent growth of coliforms and the selective system inhibits potentially
interfering microflora. A buffering system allows the enzymatic reactions to take place in the most optimal conditions.