On April 6, the FDA released a report on the investigation into the Fall 2020 outbreak of E. coli O157:H7 illnesses linked to the consumption of leafy greens. Through the use of a traceback investigation, the FDA identified the outbreak strain in one cattle feces composite sample taken alongside a road approximately 1.3 miles upslope from a produce farm with multiple fields linked to the outbreak. While no direct source or route of contamination was identified, the investigation provided insights into potential sources of contamination, including livestock activities on adjacent land.

The report also discussed trends of leafy greens outbreaks linked to the California Central Coast growing region. The FDA analyzed outbreaks that had occurred each fall since 2017 and found three key trends in the contamination of leafy greens by E. coli O157:H7 in recent years: a reoccurring strain, reoccurring region and reoccurring concerns with the potential impacts of  adjacent lands. Based on these findings, the FDA recommended that producers in the California Central Coast growing region participate in the California Longitudinal Study, which is intended to improve food safety through enhanced understanding of the ecology of human pathogens in the environment that may cause foodborne illness outbreaks. FDA also recommended the producers participate in the locally-led, locally-convened California Agricultural Neighbors (CAN) workgroup. In addition, when pathogens are identified through microbiological surveys, pre-harvest or post-harvest testing, the FDA recommended that growers implement industry-led root cause analyses to determine how the contamination likely occurred and then implement appropriate prevention and verification measures.

FDA also released an updated version of the Leafy Green Shiga-toxin producing E. coli (STEC) Action Plan which was designed to support an integrated food safety system and help foster a more urgent, collaborative, and action-oriented approach between the FDA and stakeholders in the public and private sectors. According to the FDA, since the initial publication in March 2020, the FDA has made significant progress by enhancing prevention strategies, improving response activities by the FDA and other entities, and identifying and addressing the knowledge gaps that exist around STEC contamination of leafy greens.