Qing Wang and colleagues at the Center for Food Safety at the University of Georgia said the leading cause of food-borne illness in the United States is norovirus, with produce and ready-to-eat foods being identified as the main food types responsible for these outbreaks.
Previous research showed food contamination most often occurred during preparation close to the time when food is consumed. Although virus transferred between hands, produce and food-contact surfaces are known to occur readily at this point.
For this study, the researchers looked at the transfer of the hepatitis A virus and norovirus between a range of fruit and vegetables and different kitchen knives or flat steel coarse graters.
Tests were done with uncontaminated utensils on contaminated produce and contaminated utensils on uncontaminated produce.
The study, published in the journal Food and Environmental Virology, found when using uncontaminated utensils, more than half of all knives and graters were contaminated after preparing the contaminated produce.
In addition, the study found tests using a contaminated knife or grater very often resulted in contamination of the produce being cut or grated.
In fact, after being used on one contaminated piece of produce, sterilized knives and graters were capable of cross-contaminating up to seven further pieces of produce that were chopped or grated afterwards, Wang said.