SILVER SPRING, Md. — On Nov. 20, the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention warned the American public of a multi-state outbreak of E. coli O157:H7 linked to romaine lettuce and advised against eating any romaine lettuce on the market at that time. The FDA then worked quickly with romaine producers and distributors who voluntarily withdrew the product from the market to help contain this new outbreak. This was an especially important step in advance of the Thanksgiving holiday. At the same time, we immediately launched a broad traceback investigation to determine the source of this outbreak.
We have new results to report from this investigation tracing the source of the contamination to at least one specific farm. Based on these and other new findings, we’re updating our recommendations for the romaine lettuce industry and consumers.
Shortly after our initial public warning, our traceback investigation was able to narrow down the scope of implicated product. Based on these initial findings, we immediately issued an updated public warning to consumers to avoid consuming romaine lettuce specifically from Monterey, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura counties in California. This information about the implicated regions helped consumers avoid potentially affected product. The information was provided in conjunction with a voluntary agreement that we reached with industry to provide more specific labeling information on the origin and harvest date of romaine lettuce as it was shipped to the market.
By Nov. 23, the FDA Produce Safety Network, CDC, the California Department of Public Health and the California Department of Food and Agriculture had assembled and deployed teams to inspect locations in California that were identified through the traceback investigation. The on-site investigations included farms and lettuce cooling facilities. Our teams have been on site at these locations continuously, collecting hundreds of samples for lab testing. These include soil, water and swab samples from surfaces and equipment. The majority of these results have tested negative for the outbreak strain.
The aim of this investigation is to rapidly find the cause of the contamination, what risks to consumers continue to persist, and how these potential hazards can be resolved.
Today, we’re announcing that we’ve identified a positive sample result for the outbreak strain in the sediment of a local irrigation reservoir used by a single farm owned and operated by Adam Bros. Farms in Santa Barbara county farms. The FDA will be sending investigators back to this farm for further sampling. It’s important to note that although this is an important piece of information, the finding on this farm doesn’t explain all illnesses and our traceback investigation will continue as we narrow down what commonalities this farm may have with other farms that are part of our investigation. While the analysis of the strain found in the people who got ill and the sediment in one of this farm’s water sources is a genetic match, our traceback work suggests that additional romaine lettuce shipped from other farms could also likely be implicated in the outbreak. Therefore, the water from the reservoir on this single farm doesn’t fully explain what the common source of the contamination. We are continuing to investigate what commonalities there could be from multiple farms in the region that could explain this finding in the water, and potentially the ultimate source of the outbreak.
This positive sample from the single farm was collected by the FDA and analyzed by the CDC and determined to match the outbreak strain of E. coli through Whole Genome Sequencing (WGS) analysis, the most precise DNA analysis available to us. Adams Bros. Farms is cooperating with the FDA in this outbreak investigation and we are able to confirm that this farm hasn’t shipped any romaine lettuce since Nov. 20. The company has committed to recalling products that may have come into contact with the agricultural water reservoir and we are working with the farm to determine how the contamination occurred and what corrective actions they would need to take before their next growing season.
As of Dec. 13, our investigation yielded records from five restaurants in four different states that have identified 11 different distributors, nine different growers, and eight different farms as potential sources of contaminated romaine lettuce. Currently, no single establishment is in common across the investigated supply chains. This indicates that although we have identified a positive sample from one farm to date, the outbreak may not be explained by a single farm, grower, harvester, or distributor.
While this new information does not fully explain the outbreak, it does allow us to revise our recommendations for consumers slightly. Given the identification of the outbreak pathogen on the farm in Santa Barbara county, the farms identified in the traceback, and the fact that the lettuce on the market at the peak of the outbreak should be beyond shelf-life we feel there is no longer a reason for consumers to avoid romaine lettuce from San Luis Obispo, Santa Cruz and Ventura Counties, in California, provided it was harvested after Nov. 23. If consumers, retailers, and food service facilities are unable to confirm that romaine lettuce products are from unaffected sources, we urge that these products not be purchased, or if the products have already purchased, they should be discarded or returned to the place of purchase.
Romaine lettuce that was harvested outside of Monterey, San Benito, and Santa Barbara Counties in California after Nov. 23 doesn’t appear to be related to the current outbreak. Hydroponically- and greenhouse-grown romaine also doesn’t appear to be related to the current outbreak. There’s no reason for consumers or retailers to avoid using romaine harvested from these sources.
Our investigation is ongoing. As of Dec. 13, this outbreak has resulted in 59 people becoming ill in 15 states, with the last reported illness onset date being Nov. 16. The FDA, CDC, and our partners, are also coordinating the investigation with Canadian health and food safety authorities who are also looking into a related outbreak.
Today’s update is a result of our ongoing, extensive traceback investigation with the CDC and our state partners. Traceback involves digging into records from the past to work backwards from the point of consumption or purchase of the product through the supply chain to the source. Since it’s common for people who become ill from a leafy green like romaine lettuce to have eaten the food frequently, a solid traceback investigation requires specific details about all the exposures a sick person had prior to becoming sick. So, identifying which exposures to trace back is complex and is the foundation of a successful traceback.
Once that foundation is laid, a traceback investigation often includes investigating retail establishments, suppliers, and distributors working our way back to the farm or farms that could have grown the lettuce that ended up in consumers meals and homes. It’s a labor-intensive task. It requires collecting and evaluating thousands of records while also trying to accurately document how the contaminated lettuce moved through the food supply chain to grocery stores, restaurants and other locations where it was sold or served to the consumers who became ill. We documented our extensive traceback efforts for the Spring 2018 E. Coli outbreak, to provide an example of the complexity and challenge of this type of investigation.
As we continue to investigate this outbreak, we are pleased with industry’s cooperation with our request for a “clean break” in the romaine lettuce supply available to consumers in the U.S. in order to purge the market of potentially contaminated romaine lettuce. Knowing the growing origin of produce will continue to play an important role in allowing consumers to avoid contaminated products and facilitating market withdrawals and tracebacks and why we previously called on improvements to labeling and traceability.
We’re able to report that consumers are starting to see romaine lettuce on the market labelled with the harvest origin of the romaine, along with the date of the harvest. This will improve the ability of the FDA to provide more targeted information to consumers in the event of a future outbreak of illness. We’ll continue to work with the leafy green industry on our task force to find solutions for long term labeling of romaine lettuce and other leafy greens for helping to identify products and ways to improve traceability.
This outbreak highlights the importance of moving forward with improvements in how we detect and respond to outbreaks of foodborne illness. Over the last decade, we’ve been able to link outbreaks to products more rapidly and contain the spread of illnesses faster than ever before. This owes to advances in technology that have allowed us to detect outbreaks of human illness and contamination events that may have never been previously identified. This means that in many instances we’ve been able to intervene earlier in the setting of outbreaks to reduce the number of people who are affected by a contaminated food.
We’ll continue to use advances in technology to improve our ability to track and trace products through the supply chain. We’ll be launching a comprehensive effort in early 2019 to advance our work in this area. This will help consumers get information more quickly to enable people to protect themselves and their families. We look forward to continuing our work with growers, processors, distributors and retailers in our shared efforts to protect consumers; and will continue to provide updates as information becomes available.
The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.
–U.S. Food and Drug Administration
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