The researchers tested whether Escherichia coli (E. coli) bacteria exposed to sub-lethal concentrations of three commonly-used food-grade biocides could result in greater antibiotic resistance, a greater ability to form damaging and potentially virulent biofilms and to survive normally lethal doses of biocides.

“Recent scientific evidence suggests that the selective pressure exerted by the use of biocides at sub-lethal concentrations could contribute to the expression and dissemination of antibiotic resistance mechanisms,” according to the report. They discovered increased tolerances by the bacteria.

The researchers discovered that “the increased tolerance observed suggests that the use in food environments of compounds which when used inappropriately may provide sub-lethal exposure represents a real risk for the development of adaptation to biocides.”

They say that “biofilms boost the risk of food contamination by providing a reservoir of microorganisms, and biofilm formation is a major virulence factor in human infections.”