Bacteria Can Spread Between Foods, Says New Study

A new study funded by the U.S. Food and Drug Administration shows that contained bacteria could spread from one produce item to the other through the constant use of kitchen utensils like knives or graters.

The study from the University of Georgia revealed that bacteria could latch onto a kitchen utensil found in a consumer’s home, and spread to another item. It added, though, that many consumers aren’t aware that utensils and other home surfaces could be a way for bacteria to spread. “Just knowing that utensils may lead to cross-contamination is important,” said lead author Marilyn Erickson. “With that knowledge, consumers are then more likely to make sure they wash them in between uses.”

Previously, Erickson had co-authored a study in 2013 which looked at how norovirus and hepatitis A could transfer between produce and various kitchen utensils. This study found that cutting and grating added to the count of contaminated produce items when a utensil had initially been used to process an already-contaminated item. The new study is similar to the older one, as it looks at how knives and graters influence the transfer of pathogenic bacteria between produce items. But the newer research adds a warning to consumers that bacteria could also spread in their own kitchens.

Erickson’s latest study had several types of fruits and vegetables contaminated in her lab, as she added salmonella, E. coli, and other types of pathogens that are traditionally found on those foods. She then cut into tomatoes, cantaloupe, and other produce variants to track how easily the bacteria spread when the knife was used continuously without first being cleaned. As such, Erickson and her colleagues did not wash their utensils between cutting produce items. Carrots and other produce was grated to see how pathogens spread to graters, and it was revealed that knives and graters alike can cause extra cross-contamination in the kitchen, and that the bacteria spread from item to item if the utensils weren’t washed.

On top of the above findings, Erickson also discovered that scrubbing or peeling carrots, celery, melons, and other produce did not get rid of contamination on the items, but actually contaminated the brush or peeler. These kitchen utensils were still contaminated even after being washed with running water, but the level of cross-contamination for later produce items was still dependent on the type of bacteria and the brush.