AWWA WQTC50358

Nine coliform methods are examined for sensitivity differences to naturally occurring bacteria isolated from drinking water samples. 151 samples spiked with Enterobacteriaceae (Escherichia, Klebsiella, Citrobacter, Enterobacter, Serratia and miscellaneous) and 45 samples spiked with varying densities of Aeromonas or Vibrio were tested. The older Standard Methods of Multiple Tube Fermentation, Presence/Absence and membrane filtration (mEndo LES agar) were examined as well as the newer methods employing enzyme technology; mColiBlue24(TM), Colisure(TM), Colilert18(TM), Colilert(TM), E*Colite(TM), and Colitag(TM). The method specific definitions of total coliforms are discussed and members of the Enterobacteriaceae are defined as total coliforms in this study. There are significant sensitivity differences found between methods, for Enterobacteriaceae on the whole and specifically members of Enterobacter, Serratia and other miscellaneous total colifoms. The method sensitivity to the genera and individual species are presented. Based upon the sensitivity and selectivity of the 9 methods, the indicator organism concept is discussed and concerns are raised over the selection and use of methods and interpretation of rules. Includes 20 references, tables.

Product Details

Edition:

Vol. - No.

Published:

01/01/1999

File Size:

1 file , 260 KB