Preliminary results from a multi-year study in southwestern agriculture found that concentrated animal feeding operations can be a factor in spreading strains of E.coli through airborne dust. 

The Food and Drug Administration launched a study with local partners in 2019 to evaluate how environmental factors may affect foodborne pathogens in agricultural areas in the Southwest . It centered on Yuma County, Arizona, which produces much of the leafy greens in the country. 

The study was initiated after a 2018 outbreak linked to leafy greens, according to the agency. 

Over a five-year period, researchers collected samples from irrigation water, soil, sediments, air/dust, animal fecal material, wildlife scat and other sources across a 54-mile growing region. 

Preliminary results found that airborne Shiga toxin-producing E.coli (STEC) can transfer to other locations and surfaces through dust from land to water, soil and plants. 

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The team also found increased STEC prevalence as irrigation canal water flowed past livestock and compost operations. This trend occurred without surface runoff or other direct contamination, indicating airborne dust from a nearby CAFO was a potential factor in contaminated irrigation water, particularly with southerly winds transferring CAFO dust north. 

As air sampling gradually moved away from CAFOs, the percentage of positive STEC samples steadily declined, which suggests distance may be a major factor as well. 

“The preliminary results of this study stress the interconnectedness between people, animals and the environment and serve as an important model for how to foster productive dialogue among diverse stakeholders to improve food safety,” FDA wrote in a release

The study centers around the Southwest and can be used to inform best practices for food safety in the region. However, it could help address some knowledge gaps identified in the Leafy Green STEC Action Plan around nearby land use, according to FDA. 

So far, the results are preliminary as the team continues to analyze data. Additional details are to be presented next month at the International Association for Food Protection annual meeting. 

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