The following is a statement from the FDA:
The FDA released the findings of an investigation into three outbreaks of E. coli O157:H7 illnesses that occurred in Fall 2019, all tied to romaine lettuce, that suggests the proximity of cattle to produce fields may have been a contributing factor.
Investigational Findings
The FDA worked with the Centers for Disease Control and Prevention (CDC) and state partners to investigate the contamination of romaine lettuce with several strains of E. coli O157:H7 that caused three outbreaks of foodborne illness beginning in September 2019 and which were declared over in January 2020.
Some clusters (but not all) within each of these outbreaks were traced back to a common grower with multiple ranches/fields located in the Salinas, CA, growing region. Together, the outbreaks made 188 people ill.
During the course of on-farm investigations, one of the outbreak strains of E. coli O157:H7 was detected in a sample on public land less than two miles upslope from a produce farm with multiple fields that were identified during the traceback investigations.
Other Shiga toxin-producing strains of E. coli (STEC) were found in closer proximity to where romaine lettuce crops were grown, including two samples from the border area of a farm immediately next to cattle grazing land in the hills above leafy greens fields and two samples from on-farm water drainage basins.
While these strains were not tied to the outbreaks, they do offer insight into the survival and movement of pathogens in this growing region.
These findings, together with the findings from earlier leafy greens outbreaks, suggest that a potential contributing factor has been the proximity of cattle to the produce fields identified in traceback investigations.
This is especially true when cattle are adjacent to and at higher elevations than produce fields.
In the report, “Investigation Report: Factors Potentially Contributing to the Contamination of Romaine Lettuce Implicated in the Three Outbreaks of E. coli O157:H7 During the Fall of 2019,” we’re calling on leafy greens growers to assess and mitigate risks associated with adjacent and nearby land uses, including grazing lands and animal operations.
Of note, the number of cattle observed on nearby lands during the 2019 investigations was far lower than the volume of a large Concentrated Animal Feeding Operation, offering a useful reminder that high-density animal operations are not the only factor to consider.
These key findings reinforce our concern about the possible impact of nearby and adjacent land use on the safety of leafy green crops and further underscore the importance of reviewing current operations and implementing appropriate risk mitigation strategies.
Focus on Prevention
FDA and its state regulatory partners have been working closely with the leafy greens industry to evaluate the factors that may be contributing to recurring outbreaks associated with romaine lettuce and other leafy greens.
Today, the FDA is also calling on leafy greens growers to redouble their efforts and accelerate prevention through the following mitigation strategies:
Prevent contamination from uphill adjacent cattle grazing lands, such as by produce farms increasing buffer zones if fields are adjacent to cattle grazing lands (based on assessment); and adding physical barriers such as berms, diversion ditches and vegetative strips.
Assess and mitigate risks from nearby and adjacent lands that could impact growing areas or agricultural water sources.
Increase digitization, interoperability and standardization of traceability records, which would expedite traceback and prevent further illnesses.
Perform a root cause analysis when a foodborne pathogen is identified in produce and/or the growing environment.
FDA’s 2020 Leafy Green STEC Action Plan
These and other recommendations are contained in the 2020 Leafy Greens STEC Action Plan the FDA released in March of this year.
Between 2009 and 2018, the FDA and the CDC identified 40 foodborne outbreaks of STEC infections in the U.S. with a confirmed or suspected link to leafy greens. At the FDA, we believe more can and must be done to prevent foodborne outbreaks linked to fresh leafy greens.
This plan is designed to help foster a more urgent, collaborative and action-oriented approach in collaboration with the leafy greens industry, our state partners, academia and other stakeholders to advance work in three areas: prevention, response and addressing knowledge gaps.
Our efforts to address prevention will include advancing the safety of agricultural water, enhancing inspection, audit and certification programs and continuing focused sampling assignments.
Our focus on response includes follow-up surveillance, advancing traceability and root cause analyses, and improving outbreak and recall communications.
We are working to address knowledge gaps by studying the ecology of pathogens in the growing regions and mining data from earlier outbreaks tied to leafy greens. We are looking forward to strengthening our engagement with stakeholders to bring this action plan to fruition.
New Era of Smarter Food Safety
While public health agencies have gotten better at detecting foodborne illnesses, our ability to determine the source of contaminated foods that may have caused the illnesses has lagged, due in part to the lack of modernized food traceability capabilities. Under the FDA’s New Era of Smarter Food Safety initiative, we will be laser-focused on prevention. We plan to use advances in technology to improve our ability to track and trace products through the supply chain. The New Era of Smarter Food Safety Blueprint will be launched in the coming months, which will outline how we will advance our work in this area. This will help consumers get information more quickly, enabling people to protect themselves and their families better.
We believe the entire fresh leafy green continuum can do better and we look forward to continuing our work with growers, processors, distributors and retailers in our shared efforts to protect consumers.
Together, we’ll make progress on our overarching goal to give consumers the confidence they deserve in the safety of fresh leafy greens.