Researchers Unveil More Precise E. Coli Test
Scientists from the University of Missouri have developed a new method to detect live E. coli O157:H7 cells in ground beef.
Notably, the two-step method can distinguish between dead and living E. coli cells. The research uses a technique called a real-time polymerase chain reaction (PCR), a quick, reliable method for detecting and identifying pathogens in food. However, PCR can't differentiate living from dead microbial cells. Dead cells will not make people ill, and the presence of dead cells often results in false-positive findings, which can result in unnecessary product recalls.
To prevent this, researchers developed a method to stain samples with a dye called ethidium bromide monoazide (EMA). EMA cannot penetrate live cells, but it can enter dead cells. In the dead cells, EMA binds to DNA molecules, making them insoluble and therefore invisible to PCR tests.
The researchers have had success using the new technique on ground beef, chicken and eggs. Testing takes about 12 hours, compared with older methods, which require up to two days to generate results.
