RaspberriesCloseupMainNew research out of Washington State University shows that ultraviolet C light can help kill foodborne pathogens on certain fruits. The light, which cannot penetrate opaque, solid objects, destroys the nucleic acid and disrupts the DNA of microorganisms. It’s been used for years to sanitize food contact surfaces, as well as drinking water. Shyam Sablani, an associate professor in the WSU Department of Biological Systems Engineering, and his team tested the effect of the UVC light on apples, pears, strawberries, raspberries and cantaloupe contaminated with E. coli O157:H7 and Listeria monocytogenes. The effectiveness of the treatment differed depending on the pathogen, the fruit’s surface, the dose of light and the length of exposure. For example, pears required a higher dose of light than apples to reduce E. coli, and raspberries needed more time than strawberries. Overall, the light was more effective against E. coli than against Listeria and more effective on the smoother surface of an apple or pear, inactivating up to 99.9 percent of pathogens. If contamination on the rough surface of a raspberry or cantaloupe is low, the UVC light can still reduce 90 percent of pathogens. The technique could be used on the packing line as a new way to sanitize fruits. The organic industry may be particularly interested in it as an alternative to chemical sanitizers. Further research is underway to increase the effectiveness of the UVC light on fruits with rough surfaces. The study was published in the International Journal of Food Microbiology and partially funded by a grant from the Biological and Organic Agriculture (BIOAg) program of the WSU Center for Sustaining Agriculture and Natural Resources. (To sign up for a free subscription to Food Safety News, click here.)