Test finds E. coli in beef faster, could better trace outbreaks

By Drovers news source
August 30, 2010

Infrared spectroscopy can detect E. coli faster than current testing methods and can cut days off investigations of outbreaks, according to a study at Purdue University.
Lisa Mauer, an associate professor of food science, detected E. coli in ground beef in one hour using Fourier transform infrared spectroscopy, much less than the 48 hours required for conventional plating technology, which requires culturing cells in a laboratory. Mauer said spectroscopy could be done in the same laboratories, just in much less time.

The spectroscopy method also differentiates between strains of E. coli 0157:H7, meaning outbreaks could be tracked more effectively and quickly. Current tests are multistep and take almost one week to get results.

"Even with all the other bacteria present in ground beef, we could still detect E. coli and recognize different strains," said Mauer, whose findings were reported in the August issue of the Journal of Food Science.

Mauer demonstrated two methods for separating bacteria from ground beef for testing. An antibody-capture method, which binds bacteria to antibodies attached to magnetic beads, gave results in four hours. A filtration method achieved results in about an hour.

Infrared spectroscopy could detect as little as one E. coli cell if the bacteria was cultured for six hours. Conventional plating techniques used for E. coli detection require culturing cells for 48 hours.

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