What We Know So we are left with what we know and our own hypotheses. This includes knowledge that matching samples to outbreak strains have been identified in canal water within the area of investigation, that there were anomalous weather events near the region leading up to the point when product may have been harvested and that a large concentrated animal feeding operation (CAFO) is also present in the area of investigation. The Leafy Greens Task Force has taken on the task of using this sparse information to develop recommended changes to industry’s best food safety practices. CAFOs are a recognized microbiological hazard when closely situated in areas of fresh produce production and may present varying levels of risk depending on many intrinsic factors of confined domesticated animal production as well as extrinsic environmental, topographical, hydrogeological, and crop management factors. The Leafy Greens Task Force organized a “working group” comprised of industry, academia, and other interested parties to discuss these factors, the risk they may present, common mitigation strategies to minimize risk, and to make any necessary recommendations to industry on how to further minimize the potential for microbial contamination from CAFOs. Additionally,
the group is tasked with identifying priority knowledge gaps as a prelude to recommending key solutions-based research opportunities. While this effort was born out of a rapid industry response to the severe and recent outbreak of E. coli O157:H7 linked to romaine from the desert growing region where a large CAFO is intimately proximate with fresh produce operations, it is important to emphasize that the cause of the outbreak is unknown and that this CAFO has not been specifically implicated. One important observation from this CAFO working group effort is that while the CAFO may be a reservoir for E. coli 0157:H7, there are many factors that influence the potential discharge of pathogenic bacteria from a CAFO into the surrounding area and many more factors that may determine or influence potential contamination in a field(s). These include such things as geography, weather and, perhaps most significantly, the management and best practices within. The natural tendency of our industry is to gravitate toward “buffer zones”—defined as areas set aside to account for offsite movement and deposition of, in this case pathogens, where there will be no deleterious effects. In fact, many in the supply chain are already requiring buffer zones of varying distance (most are around 1-2 miles)
that drastically restrict where leafy greens (not just romaine) may be grown. Where is the science to support the establishment of these distances? To date, the research on the offsite movement of pathogens and the subsequent deposition and survival in leafy greens fields has been sparse. The CAFO working group recommended a distance of 1,200 feet from the edge of a concentrated animal feeding operation larger than 1,000 head as a proximate safe distance and further encouraged growers to perform an aggressive hazard and risk assessment in each area where a CAFO is near fresh produce fields. Growers need to make site specific determinations based on numerous factors (some named above) as to how far away from an animal operation fields and surface water sources should be. Set distances impact property rights and economic livelihoods—but no set distance can guarantee safety. Instead, careful analysis of hazard, risk and implementation of controls should drive decisions. If approached correctly at the outset, growers can minimize the potential for contamination and prevent outbreaks, which in turn minimizes the collateral impacts associated with a CDC and FDA investigation and traceback.
34 Western Grower & Shipper | www.wga.com SEPTEMBER | OCTOBER 2018
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