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article imageUltraviolet light kills germs on some fruits, study says

By Caroline Leopold     Jul 30, 2015 in Health
Simple and inexpensive ultraviolet light technology can kill food-borne pathogens on the surface of certain fruits such as apples and pears, scientists have found.
Gardeners and organic farmers may soon have a new way to ensure the safety of fresh fruits.
Scientists at Washington State University found that ultraviolet C (UVC) light killed foodborne pathogens on the surface of certain fruits.
Study head Shyam Sablani and his colleagues ran experiments exposing UVC to pathogens on various fruits. They focused on two pathogens — Escherichia coli O157:H7 and Listeria monocytogenes — which were put on the surface of organic apples, pears, strawberries, red raspberries and cantaloupes.
Researchers found that UVC was a more effective sanitizer for E. coli than for Listeria and that the light worked better on smoother fruits like apples and pears. Light can inactivate up to 99.9 per cent of pathogens on apples and pears.
"If you have smoother skinned fruit, then this technology is really great," Sablani said.
In contrast, UVC light inactivated 90 per cent of pathogens on rough-skinned fruit like berries and cantaloupe. Bacteria was able to escape destruction by hiding within the grooves and irregular surfaces of these fruits.
UVC light is present in sunlight, but is blocked by the Earth's atmosphere so the light doesn't reach the surface.
UVC light is inexpensive and safe for the fruit, but is not yet a complete answer for sanitation. "For food safety standards, you don't want any pathogens on the fruit," Sablani said.
E. coli are bacteria found in the environment, foods, and intestines of people and animals and can cause gastrointestinal illness that lasts about a week, according to the Centers for Disease Control.
Listeria-caused illness, one type of food poisoning, is of greatest concern for pregnant women, young children, older adults and people with weakened immune systems.
Produce usually become contaminated through the soil or through handling. The FDA recommends handwashing before handling fruits and vegetables. Washing produce under cold water and scrubbing rough fruits and vegetables with a clean brush can remove germs.
The germicidal properties of UV light has been known for several years. Technology to shine UVC light as a sanitizer is already in use to kill viruses and bacteria on surfaces.
The study was published in the International Journal of Food Microbiology.
More about E coli, Listeria, UVC light, germicide
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