University of Waterloo researchers develop a cheaper and faster way to test for E. coli


Research scientists at the University of Waterloo have created an affordable and fast method for testing drinking water for the potentially deadly Escherichia coli (E. coli) bacteria.

Current tests cost an estimated US$70, and results take up to three days to return from the laboratory it is sent to for testing. However, the invention from the researchers at the University of Waterloo costs 50 cents and utilises strips of paper similar to the ones used in litmus tests to produce results that can be returned in less than three hours.

“This has the potential to allow routine, affordable water testing to help billions of people in the developing world avoid getting sick,” Sushanta Mitra, executive director of the Waterloo Institute for Nanotechnology, as well as a mechanical and mechatronics engineering professor in the university. “It is a breakthrough.”

Mitra’s research was done in collaboration with Naga Siva Kumar Gunda, a post-doctoral fellow, along with Saumyadeb Dasgupta.

The test is presently being refined by Glacierclean Technologies Inc., a start-up Mitra and Gunda co-founded.

Research scientists specifically targeted E. coli – the culprit behind a an outbreak in Walkerton, Ontario, Canada, in 2000, which claimed seven lives and sickened thousands – as it is an indicator organism in water contamination. In addition, the new test has the potential to improve water safety in remote or rural areas as well as greatly reduce the cost of testing municipal treatment systems.

The bottom of the paper strip is laced with sugar, which dissolves when placed in water. E. coli bacteria would be drawn to the sugar trail and get trapped in the porous paper when they come into contact with it. As the water continues to enter the paper, it will carry the trapped bacteria along with it and into an area of the strip that contains a mixture of chemicals. The bacteria would then react to the chemicals and if the strip turns a pinkish red, the test is positive.

When there are high levels of contamination, a result can be produced in just half an hour. Lower levels of contamination, however can take up to three hours to manifest. Work is currently underway to reduce test time.

As Mitra put it, “Simple ideas create paradigm shifts in technology and this is a simple, frugal innovation.”


Source: The University of Waterloo