DIRECT ENUMERATION OF COLIFORMS AND ESCHERICHIA-COLI BY HYDROPHOBIC GRID MEMBRANE-FILTER IN 24 HOURS USING MUG

An improved 24-hour hydrophobic grid membrane filter HGMF method for coliform and Escherichia coli enumeration was developed. The new method, which uses a buffered MUG agar for the E. coli portion of the test, was subjected to a pre-collaborative validation study against the 3-tube MPN procedure encompassing 375 naturally contaminated and inoculated samples representing 25 food products. The HGMF/MUG method produced coliform and E. coli counts equivalent to the conventional method. The confirmation rate of MUG-positive colonies in this study was 98.1%. Copyright © International Association of Milk, Food and Environmental Sanitarians.