Earlier this month, the Food and Drug Administration released an action plan to improve the safety of romaine lettuce and other leafy greens. FDA had already initiated vital research and a year-long testing program for newly harvested romaine lettuce that could help the agency uncover root causes of foodborne outbreaks.
Romaine from the Salinas, California, region tainted with E.coli sickened more than 200 people in the United States and Canada during three overlapping foodborne outbreaks last fall, and had been a recurrent issue even before then. Although FDA declared in January that the outbreaks appeared to be over, the agency also said that it will continue to investigate the underlying root causes throughout this year’s growing season.
In situations such as these, root cause analysis (RCA) can inform crucial improvements to an industry’s food safety system and stop recurring outbreaks. That’s because this investigative approach aims to answer not just what things went wrong but why they did, and which actions could prevent these problems from recurring. A new publication from The Pew Charitable Trusts, “A Guide for Conducting a Food Safety Root Cause Analysis,” describes how food businesses and public health agencies of any size can design and execute effective RCAs and benefit from their findings, even when analyses leave some questions unresolved.
FDA’s plan to monitor upcoming romaine production in Salinas addresses a common challenge in RCAs of foodborne outbreaks: Potential clues can vanish before investigators arrive. That’s particularly true when crops with short growing seasons and shelf lives, such as romaine, are involved. The agency previously traced romaine linked to many illnesses in 2019 to a specific grower, but the fields had been harvested and plowed by the time FDA staff visited the farm. The agency did not find the bacterial strains that had made people sick when it eventually sampled farm soil, water, and compost.
Observing romaine production from seed through harvest could help the agency generate, assess, and refine hypotheses about how and why contamination in recent outbreaks occurred. This, in turn, can illuminate where food safety practices fall short and how to strengthen them.
Better data on when and where lettuce contamination takes place is also key. To that end, FDA announced a year-long initiative that will test for disease-causing strains of E. coli and Salmonella in romaine samples collected after harvest but before processing. Separately, FDA, the University of Arizona, produce growers, and local irrigation water authorities have started a multiyear study to understand how disease-causing E. coli and other pathogens could reach leafy greens in fields near Yuma, Arizona.
These efforts, along with information from previous outbreaks, could yield clues about when and where romaine contamination happens and how to avoid it. Timely analysis of sampling data could also allow FDA staff to make prompt visits to farm operations to investigate a detected pathogen’s potential sources and routes of transmission to plants, before the trail of clues dries up.
Effective RCAs do not always require such extensive and protracted investigations. However, past successes with similar measures show that RCAs can help solve the kinds of recurring contamination problems seen lately in romaine.
For instance, FDA’s analyses of E. coli outbreaks linked to romaine in 2010 and 2018 did not reach conclusions about the precise origins of the outbreak strains. However, FDA did find that water likely transmitted the pathogen to crops in both cases. In response to the 2018 RCA, marketing associations for the leafy green industry in Arizona and California augmented their standards for irrigation water quality and testing.
Similarly, produce growers in Delaware, Maryland, and Virginia applied RCA methods systemwide in response to a string of Salmonella outbreaks linked to tomatoes and cucumbers that occurred frequently from the early 2000s to 2014. The analysis included tests of soil, water, animal waste, and other produce from the region. Researchers also compared test results to those from Western states where the same crops were grown but Salmonella problems appeared less prevalent. Investigators generated and evaluated several hypotheses about likely contamination pathways. Their findings informed several actions growers can take to mitigate Salmonella risks, including better management of soil amendments to reduce human health risks, changes in irrigation water sources, and offering worker training in multiple languages. Since taking these steps, growers in the region haven’t seen their Salmonella problems recur.
As these examples show, RCAs can help disrupt repeated breakdowns in food safety systems. In addition to outlining effective RCAs, Pew’s guide emphasizes that lessons from these analyses should be shared as broadly as possible so that other companies and relevant regulatory agencies can apply them and design future investigations.
However, businesses’ concerns over their legal liability for food safety problems can make them reluctant to disclose findings. Pew recommends that food industry groups and regulators develop a confidential, nonpunitive reporting system to relieve this apprehension. Such structures have improved the communication of RCA findings and strengthened safety in other sectors, including the aviation and health care industries.
Individual companies, government agencies, and other food safety professionals must learn from outbreaks and other food safety failures to develop practices that reduce risks for consumers and prevent illnesses. Challenges are bound to arise, but as illustrated by FDA’s ongoing romaine investigation, RCAs can help create a prevention-based food system.
Karin Hoelzer, a veterinarian, supports The Pew Charitable Trusts’ safe food project and leads Pew’s work on antibiotic use in animal agriculture.