Challenges of Preventing Leafy Green Outbreaks

FDA strongly encourages the leafy greens industry to adopt traceability best practices and state-of-the-art technology. This would ensure quick and easy access to key data elements from farm to fork when leafy greens are involved in a potential recall or outbreak. “Leafy greens are a highly perishable commodity; traceability information should facilitate the rapid tracking of involved product throughout the entire supply chain to expedite its removal from commerce, prevent additional consumer exposures, and properly focus any recall actions,” Dr. Gorny says.

A key element that would assist tracing efforts during an outbreak is the ability to identify specific farms or ranches that contribute to production lots, especially when the product has been comingled. While it’s important to identify where a product was grown and not simply the location of the business entity that shipped or processed it, it is equally important to be able to determine which specific farm(s) and growing region(s) are responsible for supplying the contaminated product. “This information is crucial to developing accurate public health messaging to protect the public from exposure and empower consumers to take appropriate actions,” Dr. Gorny adds.

United Fresh Produce Association and Produce Marketing Association, with input from the Romaine Task Force, are leading an initiative to include voluntary labeling on all romaine lettuce packaging that identifies its origin and a means to determine its harvest date. “Having this information will improve our ability to provide more targeted information to consumers during an outbreak,” Dr. Gorny says. “Significant progress has been made by the lettuce and leafy greens industry to assure moving forward that the growing region is clearly and uniformly labeled on romaine lettuce products.”

Without the ability to identify the growing region or specific suppliers of suspected shipments, public messaging by FDA and other public health partners during recalls or outbreaks is broad out of necessity, possibly implicating farms and growing regions that aren’t responsible for the contamination. “If supplier data are maintained when a product is comingled, it is easier to narrow the number of suspected shipments and suppliers of the contaminated product once it has been processed,” Dr. Gorny says.

But Dr. Miller doesn’t foresee improvements in supply chain traceability unless there’s a regulatory requirement. “Distributors and retailers don’t have an immediate financial reason to maintain case-level traceability, so it’s likely that the FDA will need to address this through authority granted under its Food Safety Modernization Act [FSMA] of 2011 before we see full supply chain traceability,” he says. “Essentially, supply chain traceability is no longer a technology problem; rather it’s a political and policy problem.”

To improve the traceability process, Dr. Miller believes that blockchain technology holds promise but will require operational changes in the supply before it’s fully effective. “Blockchain technology creates the ability to accurately associate transactional data across the supply chain. Companies such as distributors would have to make operational changes that would capture case-level data as shipments are received, pallets are broken down, and orders are filled for outgoing shipments,” he says. “But without operational changes like these, more integrated data systems will continue to capture data that lack the detail and granularity that public health investigators need to rapidly trace an outbreak and possibly prevent ongoing illnesses.”

Eyeing Water Safety

In addition to efforts to make it easier to identify sources of foodborne illness outbreaks, research is being conducted on how to prevent contamination from occurring in the first place. One aspect that is currently being studied is ensuring that water sources that come into contact with leafy greens are safe.

Lettuce producer and manufacturer Fresh Express formed a panel of independent scientific, production, and policy experts in November 2018 to make recommendations for new or improved ways to prevent Cyclospora outbreaks. Michael T. Osterholm, PhD, MPH, chair of the Fresh Express Blue-Ribbon Panel on Prevention of Cyclospora Outbreaks, who is also a regents professor, University of Minnesota, Minneapolis, says leafy greens outbreaks differ from other types of foodborne illness outbreaks because humans must play an essential role given that Cyclospora requires a human host to complete its lifecycle. The panel was formed as a result of 2018 Cyclospora outbreaks involving fresh produce grown and harvested in the U.S.