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Plant Leaves Protect Bacteria, Researchers Find

Engineers at the University of California, Riverside have discovered that small peaks and valleys in baby spinach leaves could be a key reason why there have been numerous bacterial outbreaks involving leafy green vegetables.
Current disinfected is put into the rinse water, and not specifically applied to the leaf surface. The researchers in the Bourns College of Engineering found that because of the varied topography of the spinach leaf nearly 15 percent of the leaf surface may reach concentrations as low as 1,000 times that of the bleach disinfectant being used to rinse it.
“In a sense the leaf is protecting the bacteria and allowing it to spread,” says Nichola M. Kinsinger, a post-doctoral researcher working with Sharon Walker, a professor of chemical and environmental engineering. “It was surprising to discover how the leaf surface formed micro-environments that reduce the bleach concentration and in this case the very disinfection processes intended to clean, remove, and prevent contamination was found to be the potential pathway to amplifying foodborne outbreaks.”
Future research will focus on a broader range of foods, surfaces in processing facilities and pathogen types, Kinsinger said.
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