New Study Points to Benefits of Conservation for Food Safety

fs-PNAS_study_farm_image.jpgOn August 2015, the journal, Proceedings of the National Academy of Sciences, released the findings from a study that revealed that the elimination of natural vegetation surrounding farm fields failed to reduce the presence of foodborne illness-causing pathogens in fresh produce grown in those fields. The study, titled "Comanaging fresh produce for nature conservation and food safety," found not only that the absence of natural vegetation did not contribute to pathogen reduction, but also that cleared land resulted in increased pathogen prevalence over time.



This study harkens back to the 2006 E. coli outbreak in bagged spinach, which resulted in significant removal of vegetation and destruction of conservation practices in large swaths of California's Central Coast (termed the "lettuce bowl" of the United States, as the region produces more than 70% of the nation's leafy greens and other vegetables). Following this outbreak, which resulted in three fatalities and sickness in hundreds of others, growers responded to buyer pressure to take measures to prevent wildlife intrusion, believed to be the disease vector.

Wildlife's role in this pathogenic outbreak was never clearly identified, but these new industry standards encouraged producers to remove conservation practices they had implemented on their vegetable farms. These practices included grassed filter strips, streamside vegetation, and windbreaks that reduce the movement of pathogens, nutrients, and pesticides into surrounding water bodies and onto crops, in addition to creating habitat for wildlife.

The habitat created and maintained through these working lands conservation practices supports species such as pollinators, other beneficial insects, and birds of prey that often lessen the need for chemical inputs to control agricultural pests. Despite these clear economic and environmental benefits - and despite no explicit regulatory language requiring such land clearing - conservation practices that add to wildlife habitat have become perceived food safety risks since this outbreak.

Study Findings
By combining land use maps with pathogen prevalence in produce, irrigation water and rodents, the researchers found that from 2007 to 2013 enterohemorrhagic E. coli (EHEC) prevalence in fresh produce increased by more than an order of magnitude, despite widespread vegetation clearing at farm field margins in the California Central Coast region. When growing fields were near grazing lands, pathogens increased. However, conservation practices that filter pathogens could be used to reduce risk. They found no evidence of increased EHEC, generic E. coli, or Salmonella near non-grazed, semi-natural areas. Instead, they found that pathogen prevalence increased the most on farms where non-crop vegetation was removed.

This study's findings directly oppose the belief that vegetative clearing and elimination of wildlife near produce fields works as a pathogen reduction strategy. Instead, it supports the idea that successful food safety reform can incorporate wildlife habitat and conservation practices with the end goal of protecting human health.

Study Recommendations
Collaboration among growers, ranchers, and feedlot operators is encouraged. Such practices include planting low risk crops between leafy green vegetables and areas of higher incidence of pathogens; reducing agri-chemicals to bolster beneficial bacteria that predate and compete with E. coli; vaccinating cattle that can carry high levels of E. coli pathogens; attracting livestock away from waterways using water troughs and supplemental feed; creating secondary treatment wetland near feedlots; and maintaining diverse wildlife communities with fewer disease hosts.

What is Co-Management?
The concept of "co-management" refers to practices that simultaneously achieve conservation goals and reduce pathogen risks on the farm. Co-management means approaches to farm management that respond to site-specific conditions by integrating cultural, biological, and mechanical practices that promote ecological balance by conserving biodiversity, soil, water, air, energy, and other natural resources, while also reducing pathogen hazards associated with food production. Examples of practices that support conservation and food safety include planting cover crops and using compost to foster diverse soil microbial life that aid in suppression of pathogens; installing vegetative buffers that reduce pathogen movement in air and water; and monitoring the crop for animal feces and signs of feeding, and if found, not harvesting that area.

Implications for FSMA
With the rollout of the Food and Drug Administration's (FDA) final food safety rules for produce farms and food processing facilities in the coming months under the Food Safety Modernization Act (FSMA), this study is quite timely. This research confirms what NSAC, Wild Farm Alliance and our other members have long been advocating: that productive farms can co-manage for conservation and food safety -- minimizing the risks of foodborne illness while conserving and building resilient ecosystems.

In both the proposed rule and the re-proposed sections, FDA acknowledges that it fosters and encourages co- management, but does not define co-management and overlooks opportunities to build conservation considerations into the standards. For example, the proposed Produce Rule outlines standards for training personnel who participate in the growing, harvesting, packing, and holding of produce, but there is no requirement to include co- management principles and practices in that training. One way to strengthen co-management in the produce safety regulations would be to define and include this concept more directly in training requirements.

The most recent version of the proposed regulations include a new provision intended to avoid inadvertently promoting or encouraging practices that adversely affect wildlife and animal habitat, including impacts on threatened or endangered species. This new provision would be part of the regulations themselves, and would specifically state that nothing in the Produce Rule requires covered farms to take measures to exclude animals from outdoor growing areas, or to destroy animal habitat, or otherwise clear farm borders around outdoor growing areas or drainages. This is a significant improvement from the original proposal. However, it will require ongoing monitoring as the rules are implemented, to ensure that continued pressure from buyers does not interfere with the intention behind the standards.

For more updates on FSMA, check out NSAC's latest two-part series on FSMAimplementation and appropriations.

Editor's Note: Jo Ann Baumgartner of WFA and Sophia Kruszewski of NSAC co-wrote this article with help from Carla Curle, NSAC Policy Intern. Sophia is a policy specialist with the National Sustainable Agriculture Coalition (NSAC) and leads the coalition's work on food safety together with NSAC's Food Systems Integrity committee. Sophia holds a law degree from Vermont Law School and studied environmental science at the University of Michigan.

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