An Automated Detection Technology for On-Site E. coli and Coliform Bacteria Monitoring

We have developed a new detector for Escherichia coli and coliform bacteria that can be used on site with automated signal analysis. Fluorogenic “targeted substrates” and a fibre-optic detector monitor glucuronidase and galactosidase enzymes as indicators for E. coli and Total Coliform, respectively. The test has been certified by AOAC and approved for use in laboratories by the Ontario Ministry of the Environment. The test has been demonstrated on samples from drinking water to sewage, with no change in the analysis method and no need for dilutions. Single organisms were detected in about 13 h, with highly contaminated samples detected earlier. The bacteria were quantified using the continuous signal and a model for growth kinetics. Sample-to-sample repeatability was similar to plate-counting methods. The calibration function for a new site or type of bacteria can be adjusted using a small number of samples.