Determination of the Specificity and Sensitivity of a Novel Rapid Bacteria Test for Detecting Indicator Organisms in Water Samples

By Wendy J. Dixon and Elie Arslan.

Published by Food Studies: An Interdisciplinary Journal

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A novel rapid test for detecting the presence of bacteria in water, the Watersafe Rapid Bacteria Test (referred to here as “Watersafe Test”), was examined for its ability to detect indicator organisms. The general methods used for detecting indicator organisms in water samples are time consuming and involve use of special culture media. However, the Watersafe Test is a rapid antibody-based method that can be performed in seventeen minutes without a need for lab equipment, lab space, or special media and thus could be performed at a water source. The Watersafe Test was evaluated, in this study, for its sensitivity in detecting E. coli, a fecal indicator organism, by the standard plate count method. The results indicated that the Watersafe Test detects E. coli strain ATCC 700620 at 2,930 CFU/ ml or greater. To determine the specificity of the Watersafe Test for E. coli and other significant bacteria as indicators of water quality, sixty-three species or strains of bacteria were tested. All E. coli samples tested produced a positive result for E. coli, while some other bacteria also gave a positive result. The majority of the bacteria that tested positive belonged to the Enterobacteriaceae family and would indicate poor water quality. A few other types of bacteria were also detected, however, most of these bacteria would not be found in water, either naturally or through common contamination routes. The results from this study show that the Watersafe Test method can detect poor microbial quality in water, which is considered a potential health risk. Although not as sensitive as conventional methods for detecting indicator organisms, the Watersafe Test is relatively rapid, inexpensive, requires no laboratory facilities and could be used directly in the field.

Keywords: E.coli, Indicator Organisms, Microbial Quality, Water Testing, Antibody-based Method, Waterborne Disease, Foodborne Disease

Food Studies: An Interdisciplinary Journal, Volume 4, Issue 1, January 2015, pp.1-18. Article: Print (Spiral Bound). Article: Electronic (PDF File; 710.392KB).

Dr. Wendy J. Dixon

Professor, Department of Biological Sciences, California State Polytechnic University at Pomona, Pomona, CA, USA

Elie Arslan

Student, Department of Biological Sciences, California State Polytechnic University at Pomona, Pomona, CA, USA