Detection and survival of coliforms in drinking water

Recovery of chlorine injured coliforms inoculated into potable water containing high numbers of heterotrophic plate count (HPC) bacteria was enhanced by anaerobic incubation of membrane filter (MF) cultures on m-endo LES agar rendered non-selective by removal of sodium lauryl sulfate (SDC) and sodium desoxycholate (SDC). Modification of mendo LES resulted in a 1.3 fold increase in recovery of Klebsiella pneumoniae, Enterobacter aerogenes, and Enterobacter cloacae. Recovery of injured Escherichia cou i and Citrobacter freundii was not significantly enhanced. Anaerobic incubation markedly reduced growth of HPC bacteria on MF and unmasked coliform detection.