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Standard dishwashing method does not eliminate stomach flu virus

Category: Infectious Diseases

Recent researched published online by the journal PLoS ONE has found that although the standard methods of dishwashing can kill bacteria, they may not rid plates and silverware of the stomach flu, norovirus, which can be detected with a lab test.

"We know that when public food establishments follow the cleaning protocols, they do a very good job at getting rid of bacteria," said research author Melvin Pascall, associate professor in the Department of Food Science and Technology at Ohio State University. "Now we can see that the protocols are less effective at removing and killing viruses - and this may help explain why there are still so many illnesses caused by cross-contaminated food."

Funded by a grant from the Ohio State Center for Clinical and Translational Science, Pascall and his colleagues analyzed how well the norovirus stood up to the traditional hand-washing and mechanical washing procedures of restaurants. For the study, they introduced the stomach flu virus and the bacterial strains E. coli K-12 and L. innocua into reduced-fat milk and cream cheese, which was applied to tableware and silverware, like stainless steel utensils, ceramic plates and glassware.

The results showed that the mechanical dishwasher and the hand-washing method effectively reduced the levels of bacteria on the tableware, but both methods were ineffective in reducing the norovirus to safe levels.

Kurt Stevenson, M.D., professor of internal medicine and epidemiology in the Division of Infectious Diseases at Ohio State's Wexner Medical Center, who was not part of the study, noted that the stomach flu virus is easily spread among populations in which people are in close proximity to one another and that the virus can easily be transferred to food.

The study authors reported that the findings indicate that updated procedures are necessary for protecting the public from contracting the stomach flu.