An enzymatic procedure for the confirmation of total coliforms and Escherichia coli enumeration from water.

A new procedure for the confirmation of total coliforms and Escherichia coli from presumptive most probable number (MPN) test is described. The procedure utilizes an enzymatic test apparatus composed of a couple of devices, one charged with ONPG-medium for the detection of beta-galactosidase, the other with PNPG-medium for the detection of beta-glucuronidase. The results obtained demonstrate that the procedure is sensitive, specific and accurate. Further, it presents some advantages from the practical point of view: the cost of the devices is relatively low, their use is extremely simple and short time consuming, a single thermostatic apparatus adjusted at 36 degrees C for the incubation of the devices is only required, the results can be obtained after 18 h without any apparatus for the lecture (e.g. UV apparatus), they are not submitted to subjective interpretation.