Garden Microbe Battles E. Coli in Laboratory Tests

It's a battle among the microbes, and Agricultural Research Service (ARS) geneticist Michael Cooley knows the winner. In studies that begun in 2002, Cooley showed that a garden-friendly microbe, Enterobacter asburiae living peaceably on the beans and cucumbers can significantly reduce the levels of two pathogens--Escherichia coli O157:H7 and Salmonella enterica. Follow-up experiments with green leaf lettuce were conducted. Cooley found that a rather ordinary bacterium, Wausteria paucula, befriended E. coli and enhanced its survival six-fold on lettuce leaves. Adding E. asburiae to the experiment again demonstrated this beneficial microbe's ability to suppress E. coli. When lettuce leaves were exposed to the three kinds of microbes, E. asburiae decreased E. coli survival 20- to 30-fold.

More remains to be learned about the competition that takes place--among the microbes--on leaves or other plant surfaces. In the meantime, E. asburiae shows initial promise for use as a biological control agent in science-based strategies to make salad greens much safer to consume, Cooley reports.

The complete press release is available at http://www.ars.usda.gov/is/pr/2008/080721.htm.