Improper chemical use puts public health at risk

Alarming use of biocides - chemicals used to suppress organisms that are harmful to human or animal health - in the food industry may endanger your health.

Biocides used in food production at sub-lethal doses may put public health at risk by increasing antibiotic resistance in bacteria and enhancing their ability to form harmful biofilms, said a study published in Applied and Environmental Microbiology.

Biofilms boost the risk of food contamination by providing a reservoir of microorganisms and biofilm formation is a major virulence factor in human infections.

The researchers exposed Escherichia coli bacteria - that can cause serious infections - to sub-lethal concentrations of three food-grade biocides.

"We found that it resulted in greater antibiotic resistance, a greater ability to form damaging and potentially virulent biofilms and to survive normally lethal doses of biocides," said Rosa Capita of the University of Leon, Spain.

Exposures to the biocide sodium nitrite increased resistance to 14 out of 29 antibiotics tested. E coli cells also acquired tolerance to the biocides, especially sodium nitrite and sodium hypochlorite, and these two biocides improved the microbes' ability to form biofilms.

On the other hand, exposure to the biocide trisodium phosphate actually reduced E coli's ability to form biofilms, and boosted resistance only to a single antibiotic, said the study.

"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," added Capita.

"The results are important in demonstrating the need to guide policies to prevent improper use of biocides," concluded Capita.