CHLORINE INJURY AND THE COMPARATIVE PERFORMANCE OF COLISURE(TM), COLILERT(TM) AND COLIQUIK(TM) FOR THE ENUMERATION OF COLIFORM BACTERIA ANDESCHERICHIA-COLI IN DRINKING-WATER

Several factors have stimulated interest in recently developed substra te specific media for the detection of coliform bacteria in water. Thi s study compared the performance of Colisure(TM) (Millipore), ColiLert (TM) (Environetics) and ColiQuick(TM) (Hach) with accepted membrane fi ltration and MPN methodologies for the enumeration of total coliforms and E. coli in chlorinated water. The performance of all three media w as compared, in MPN configuration, with LTB/MPN (confirmed) using a va riety of drinking and source water samples, both with and without chlo rination. The Cochran-Mantel-Haenszel test yielded statistical correla tions between results obtained with each of the three new enzyme detec tion media and accepted reference methods for the detection of low num bers of total coliforms. Another series of tests compared the performa nce of Colisure with accepted methods (LTB/MPN confirmed with BGLB and EC-MUG) in the detection of total coliforms and E. coli in sewage-spi ked samples simulating contaminated drinking water, using an USEPA/AWW A test protocol. The results demonstrated that Colisure detected these indicator bacteria with greater sensitivity than the accepted methods and that this difference increased between 24 and 28 hours of incubat ion. The results of this study collectively support the validity of th e new enzyme detection method for the detection of low levels of colif orm bacteria and E. coli in source water and contaminated drinking wat er.