Enumeration of Indicator Organisms in Foods Using the Automated Hydrophobic Grid-Membrane Filter Technique

The automated HGMF technique was compared against accepted traditional methodology for the recovery and enumeration of coliforms, Escherichia coli , enterococci and Staphylococcus aureus from a variety of naturally and artificially contaminated foods. The overall ratios of recovery of the HGMF relative to conventional methods were 0.88 for coliforms, 0.80 for E. coli , 0.81 for enterococci and 0.80 for S. aureus . Our results suggest that the automated HGMF system is a viable alternative to conventional most-probable-number and spread plate techniques for the isolation and enumeration of foodborne microorganisms on selective media; however, consideration must be given to modifying procedures for the optimal recovery of stressed cells by this automated membrane filtration technique.