In a recent study funded by the U.S. Food and Drug Administration, UGA researchers found produce that contained bacteria would contaminate other produce items through the continued use of knives or graters. The bacteria would latch on to the utensils commonly found in consumers’ homes and spread to the next food item.
Unfortunately, many consumers are unaware that utensils and other surfaces at home can contribute to the spread of bacteria, said the study’s lead author Marilyn Erickson, an associate professor in the College of Agricultural and Environmental Sciences’ food science and technology department.
“Just knowing that utensils may lead to cross-contamination is important,” Erickson said. “With that knowledge, consumers are then more likely to make sure they wash them in between uses.”
Erickson has been researching produce for the past 10 years. Her past work mainly has focused on the fate of bacteria on produce when it’s introduced to plants in the field during farming.
In 2013, she co-authored a study that looked at the transfer of norovirus and hepatitis A between produce and common kitchen utensils. The study determined that cutting and grating increased the number of contaminated produce items when that utensil first had been used to process a contaminated item.
This study, published in Food Microbiology, is similar in that it considers the influence that knives and graters have on the transfer of pathogenic bacteria to and from produce items. She urges consumers to realize that these germs can spread in their kitchens as well.
Researchers have known that poor hygiene and improper food preparation practices in a consumer’s home can lead to foodborne illnesses, but considering what practices in the kitchen are more likely to lead to contamination has not been examined extensively.
In her recent study, Erickson contaminated many types of fruits and vegetables in her lab—adding certain pathogens that often can be found on these foods, such as salmonella and E. coli.
Using a knife, Erickson would cut into tomatoes, cantaloupe and other types of produce to see how easily the bacteria could spread when the knife continuously was used without being cleaned. Because they “were looking at what would be the worst-case scenario,” she said, Erickson and study co-authors did not wash between cutting these different produce items.
Researchers also grated produce, like carrots, to see how easily the pathogens spread to graters. They found that both knives and graters can cause additional cross-contamination in the kitchen and that the pathogens were spread from produce to produce if they hadn’t washed the utensils.