Researchers have developed a rapid test using a simple paper strip that can detect E. coli in swimming pools within minutes.
The new tool, developed by McMaster University researchers, can close the gap between outbreak and detection, improving public safety.
Scientists from the Sentinel Bioactive Paper Network have created and validated the viability of the test strip, which can detect potentially harmful concentrations of E. coli in water quickly and simply, with much greater accuracy than existing portable technology, the journal Analytical and Bioanalytical Chemistry reports.
"Coliforms are always a big problem," says John Brennan, McMaster chemistry professor who led the study. "The methods used to detect outbreaks are slow, and tend not to be portable, as they often need a lab-based amplification step prior to testing, causing a time lag between an outbreak and a beach closure."
Bioactive paper is both old and new, Brennan explains. Since the late 1950s, physicians have been using bioactive paper to test for glucose in urine, according to a McMaster's statement.
The new strips are coated with chemicals that react to the bacteria, and are printed using inkjet technology similar to that found in standard desktop printers. Within 30 minutes of sampling, the paper changes colour to indicate the presence of E. coli, with colours coded to represent different forms and concentrations of the bacteria.
In the future, the test should make it possible for consumers to check their water affordably and easily, without additional equipment, scientific knowledge or long waits.
The standards for safe drinking water are hundreds of times tighter than those for safe swimming water. Typically, limits for safe swimming allow for a maximum of 100 to 500 cells in 100 ml of water, depending on jurisdiction.
For water to be considered safe for drinking, there cannot be even one cell in 100 ml - a little less than half a cup of water. Commercialization of a final product could take as little as two to three years.