Antithetical to the natural food movement, large-scale traditional food producers may be endangering public health with the use of sub-lethal doses of biocides, investigators the University of Leon conclude in one of the first scientific studies to even probe the issue. In the United States, food producers typically use three types of biocides, a category that includes pesticides and antimicrobials.
Investigator Rosa Capita and her colleagues designed the study to determine whether Escherichia coli might gain antibiotic resistance following exposure to sub-lethal amounts of three types of biocides used in food products. They also wanted to see whether the bacteria would gain a greater ability to form biofilms potentially virulent and deadly to humans. "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," the investigators wrote in a paper published Monday.
In the study, Capita found that exposures to sodium nitrite – a widely used biocide found in hot dogs, among other processed food products – boosted resistance by the e. coli to 14 of 29 antibiotics tested by the Spanish investigator. Even worse, the use of biocides may prove counterproductive, as e. coli developed resistance to the pesticide itself.
"These findings are in agreement with reports of other authors, where adaptation of E. coli to both chemical and physical sub-lethal stresses has been demonstrated," Capita wrote. "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."
However, the relationship between biocides and e. coli proved somewhat complex, as exposure to trisodium phosphate reduced e. coli’s ability to form biofilms, while increasing resistance to just one antbiotic. Deemed one of the top threats to public health in the 21st century, drug-resistance bacteria threatens to undue a century of progress in medicine and public health, rendering useless many procedures seen today as routine. As biofilms provide nurturing homes to microbial pests, the use of biofilms proves doubly dangerous – on both sides. The continued use of biocides in many food products may help dangerous pathogens to develop, while stripping humanity of one its greatest medical triumphs.
Capita said she hoped the study would convince food producers and regulators to reconsider the use of pesticides and antimicrobials in many foods on the market.
Source: Capital, Rosa. Improper Use Of Biocides In Food Production May Endanger Public Health. Applied And Environmental Microbiology. 2013.