FDA announces further findings from leafy greens E. coli outbreak
The FDA, along with CDC and state and local partners, investigated a multistate outbreak of E. coli infections in the fall of 2020. The epidemiology and traceback investigation have determined that the outbreak was linked to leafy greens.
The epidemiological and traceback investigations were not able to determine a specific type of leafy green linked to illnesses. On Dec. 22, 2020, the CDC announced that this outbreak appears to be over.
This outbreak, announced by FDA and CDC on Oct. 28, 2020, was caused by a strain of E. coli that is genetically related to a strain linked to the fall 2019 romaine outbreak.
The FDA completed a traceback investigation of multiple types of leafy greens identified in patient interviews. Although no single ranch was identified as a common source of the leafy greens, FDA and state partners also conducted on-site investigations on farms of interest.
Teams were deployed to dozens of ranches in the region to conduct large scale environmental sampling. Additionally, no Shiga toxin-producing E. coli were found on leafy greens. As part of the field investigation, teams conducted environmental sampling on and around ranches of interest to identify any factors that could have led to contamination. Samples of soil, scat or animal droppings, compost, water and other environmental sources were collected and analyzed.
Laboratory analysis of samples is now complete. The analysis has confirmed a positive match to the outbreak strain in a sample of cattle feces, which was collected during follow-up investigations on a roadside, uphill from where leafy greens or other food identified in the traceback investigation were grown. While the finding does not provide definitive information on how E. coli may have contaminated product during the growing and harvesting season, it does confirm the presence of a strain of E. coli O157:H7 that causes recurring outbreaks in a more narrowly defined growing region and a potential, continued source of contamination.
At this time, FDA’s investigational activities have concluded. The FDA continues to review the findings from this outbreak and a detailed report will be released in the near future. This report will include recommendations shaped by the investigation findings.
In the meantime, as recommended in our Leafy Greens Action Plan, the FDA continues to recommend growers assess and mitigate risk associated with adjacent and nearby land use practices, particularly as it relates to the presence of livestock, which are a persistent reservoir of E. coli O157:H7 and other STEC.
Produce Marketing Association (PMA) response
On Jan. 27, the FDA provided an updated release detailing the findings of their investigations into a composite assessment of the 2020 outbreaks involving E. coli O157:H7. While the investigation is concluded, the FDA’s final report is forthcoming. Notably, the latest developments indicate that while this investigation has been tied to leafy greens, no specific type, brand, or supplier has been identified as a source of infection. Additionally, the investigation identified the outbreak strain in a sample of manure from a roadway in the vicinity of production sites of interest.
PMA acknowledges the effort and significant resources allocated to this comprehensive investigation and recognizes the broad cooperation demonstrated by the produce industry in the California Central Coast region during the fall crop production season. A systems-based approach with extensive collaboration is critical for the industry to continue to provide the safe, nutritious and delicious products that are essential to our population’s health.
With respect to the ongoing, multipronged, efforts by associations, leafy greens industry consortia, Center for Produce Safety and CDFA advisory groups to tackle root cause analysis, we strongly encourage the FDA to initiate sharing of the details of the investigative findings with these groups at this time. This timing is critical to allow these private-public partnerships to fully capitalize on opportunities to provide science and risk-based guidance in advance of the rapidly approaching production season.
The burden to ensure and maintain the safest food supply is not only for our industry to bear. PMA continues to strongly advocate for the investment in understanding root cause analysis, improving practices to support compliance with the Produce Safety Rule and Leafy Greens Action Plan, and as reinforced by the FDA’s latest findings, prioritizing broad cooperation across the co-regionalized agricultural sectors in implementing practices that mitigate the persistence and transfer of STEC from adjacent land and environmental reservoirs and within the crop production environment.
