Description
The 3M Petrifilm E.coli/Coliform Count plates yield a count for E.coli and Total Coliforms, with confirmed results available in 24-48 hours. These plates come as a ready-to-use medium system containing Violet Red Bile (VRB) nutrients, a cold-water soluble gelling agent, an indicator of glucuronidase activity (BCIG), and a tetrazolium indicator that allows for colony enumeration in food and beverage samples.
To confirm E.coli, look for blue to red/blue colonies associated with entrapped gas, regardless of their size or colour intensity. Other Coliform colonies are red and closely associated with entrapped gas within one colony diameter. Colonies without gas (i.e., a distance greater than one colony diameter between colony and gas bubble) are not considered as coliforms.
The Total coliform count includes both red and blue colonies associated with gas at 24 hours. Any blue colony associated with gas that appears within the validated method incubation period is confirmed as E.coli.
