Cutting fruits and vegetables doesn't just leave a knife slick with juice and pulp; it can spread viruses to the knife if the produce isn't clean, according to a new study. Scientists already knew that bacteria could contaminate utensils in this way, but the new study is the first to look at hepatitis A virus and norovirus, the most common cause of foodborne illness in the United States. The findings could help food safety investigators pinpoint the source of foodborne illnesses and develop new methods to prevent outbreaks.
These findings could help food safety investigators pinpoint the source of foodborne illnesses and develop new methods to prevent future outbreaks. The researchers set up a test kitchen and developed techniques to strip viruses off knives and graters. They measured the amount of hepatitis A virus or norovirus transferred from contaminated honeydew melons, cantaloupes, tomatoes, strawberries and cucumbers.
Regardless of the material and the sharpness of the knife used, more than half of all samples transferred viral particles to the knife. Some combinations of viruses and produce were more likely to contaminate knives than others. Norovirus was transferred more often from strawberries and cucumbers than hepatitis A, while melons and tomatoes transferred more hepatitis A than norovirus. Similar experiments on viral transfer from carrots to a grater found cross-contamination the majority of the time.
The scientists then tested whether contaminated knives could transfer viruses to clean fruits and vegetables, finding that at least seven produce items could be contaminated by a single contaminated knife. The results indicate that foodborne viruses are just as likely to spread to utensils as bacteria are. Since other studies have shown that fewer than 20 norovirus particles are needed to make someone sick, the viral knife contamination could cause illness.
This data is useful for commercial kitchens, where many produce items bound for different meals are being simultaneously chopped. It’s recommended that people wash their hands and utensils in between chopping produce items.
