How is E. coli measured?
The Burlington Wastewater laboratory uses the IDEXX laboratory’s Quantitray method for analyzing recreational waters. This method is used for the simultaneous detection, specific identification, and confirmation of total coliforms and E. coli in the water. It uses indicator nutrients that cause target microbes contained in the sample to produce a color change or fluorescence, both indicating and confirming their presence. Non-coliform bacteria are suppressed and cannot metabolize the indicator nutrients from the media. Consequently, they do not interfere with the specific identification of the target microbes during incubation. Unlike other methods for bacteria analysis that require a 24-hour incubation period, IDEXX has developed a media that provides results in 18-hours. By using this media, Burlington can run samples in the early afternoon and report beach closures by the next morning.
