Direct Enumeration of Coliforms and Escherichia coli by Hydrophobic Grid Membrane Filter in 24 Hours using MUG

Abstract

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 precollaborative 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%.