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TAG February 28, 2019 0 Comments

FDA’s use of whole genome sequencing (WGS) was a significant factor in its late 2018 investigation of an E. coli outbreak tracked to romaine lettuce. Not only had 83% of the 36 ill consumers interviewed report that they had eaten romaine lettuce the week before illness onset, but all the E. coli O157:H7 isolates from ill consumers were found, through WGS, to be closely related to one seen in ill consumers in the U.S. and Canada in the 2016 and 2017 outbreaks. Although FDA was not able to conclusively identify the food in those outbreaks, romaine lettuce was the suspect food in 2017 based on epidemiological and traceback information, as well as investigation results from Canadian public health officials, who were able to identify romaine lettuce as a suspect food vehicle in 2017 because a majority of ill consumers in Canada reported consuming romaine. FDA did not declare the same in that case because U.S. persons who fell ill reported consuming various types of leafy greens, but there was not the same level of specificity in reporting romaine consumption. As we mentioned in last week’s newsletter, FDA published its Investigation Summary in mid-February detailing this and the factors potentially contributing to the contamination of the 2018 romaine lettuce outbreak for which there were 62 reported illnesses in 16 states and the District of Columbia, resulting in 25 hospitalizations and two cases of hemolytic uremic syndrome (HUS). The investigation summary comes just after FDA’s reminder that it will begin routine Produce Safety Rule (PSR) inspections of large farms this spring. Following are key points of the investigation summary and PSR inspection announcement. FDA’s recommendation that consumers not eat any romaine and that industry withdraw product and withhold distribution was based on the fact that the agency was able to identify romaine lettuce as the suspected food but not the exact growing locations and dates of harvest from available traceback records, and the outbreak appeared to be ongoing. Traceback was initiated from six points of service that identified 14 distributors, 17 farms and 15 ranches (i.e. specific fields) in multiple California counties as potentially supplying the contaminated romaine lettuce; on-site investigations were conducted of the identified farms and lettuce cooling facilities. The traceback first identified the likely source to be within a specific California growing region, then narrowed to identify three California counties, with information communicated to the public at each finding. From that point, the historical, epidemiological and traceback analyses from the 2016 and 2017 outbreaks aligned with the new information helped prioritize investigations of romaine lettuce farms. The suspected farm was identified through a sediment sample taken from an on-farm water reservoir in Santa Maria in Santa Barbara County, California, which tested positive for the outbreak strain. The farm had also been identified in multiple legs of the fall 2018 traceback investigations and as one of the potential suppliers in the 2017 investigations. Once identified as a suspect, the farm also recalled red leaf lettuce, green leaf lettuce and cauliflower that may have been contaminated. It could not be conclusively confirmed, however, that this farm was the sole source of the outbreak because not all the traceback legs led to it, but the report stated that this also may be due to ill consumers having multiple romaine lettuce exposures and limited recollection of exposures and brands they ate. Additionally, only a few relatively small clusters of people (reporting eating a food from the same restaurant or retail store) were identified, and it is possible that additional unidentified foods may have contributed to the outbreak. To identify the business(es) responsible for an outbreak, gather information about potential contributing factors, and determine potential regulatory action, FDA uses a spectrum of procedures that includes facility and on-farm inspections, investigations and environmental assessments. In this case, the investigation was conducted by the FDA’s Produce Safety Network, CDC, the California Department of Food and Agriculture (CDFA), and the California Department of Public Health (CDPH). It included on-farm observations, environmental sampling and interviews. The primary areas of focus were agricultural water; equipment, tools, and sanitation soil amendments; growing and harvesting practices; animal intrusion; adjacent land use; and employee health and hygiene practices – the key elements of the PSR and GAPs. Although the precise route of contamination is uncertain, interviews with the grower indicate several plausible routes, including direct harvest/postharvest application and/or use of reservoir water on harvest equipment food contact surfaces. Additionally, while the farm did have a procedure for testing and treating the water, inspections showed that verification procedure records did not show the water sanitizer to be at sufficient levels; water tank sanitizer treatment systems had undissolved sanitizer cakes; some tank systems were constructed so as to likely not allow for optimal sanitizer treatment of the water; and untreated reservoir water was used to spray roads for dust abatement which were traveled by harvest equipment. Thus, FDA could not rule out other sources or means of contamination. Although the investigation team did not identify any obvious route of reservoir contamination, evidence of extensive wild animal activity near the contaminated reservoir sediment was noted and adjacent land use of soil amendments or animal grazing may have contributed. Additionally, foodborne illness outbreaks caused by this strain of E. coli O157:H7 occurred in 2016, 2017, and 2018, indicating that it may have persisted in the environment or been repeatedly introduced from an unknown source. What does it mean to you? FDA makes a number of recommendations in the report, with key recommendations including: All segments of the leafy greens industry thoroughly review current operations, procedures, policies and practices taking into consideration the findings of this investigation report, the FSMA Produce Safety Rule, the FSMA Preventive Controls for Human Foods Rule and other relevant FSMA regulations. Specifically, FDA recommends that growers assure that all agricultural water is safe and of adequate sanitary quality for its intended use and perform a root cause analysis when a foodborne pathogen is identified to determine the likely source of the contamination, if prevention measures have failed, and whether additional measures are needed to prevent a reoccurrence. Real-time procedures be developed to quickly explore the possible scope, source(s) and route(s) of contamination when pathogens are detected by routine pre-harvest or finished product verification testing, and findings be shared among the leafy greens and produce industry. Leafy green growers, buyer/shippers, and retailers be able to trace product back to the specific source in real time and make information about the source, such as harvest date and standardized growing regions, readily available for consumers, like the voluntary labeling program developed in response to the outbreak. Traceability best practices and state-of-the-art technology be adopted by the entire leafy greens supply chain to assure quick, accurate and easy access to key data elements from farm to fork when leafy greens are involved in a potential recall or outbreak. PSR Inspections The coinciding of this report and its recommendations with FDA’s “reminder” announcement that routine PSR inspections will begin this spring is also telling – and should put all farms on high alert. It’s no coincidence that the report notes that 28 foodborne illness outbreaks of Shiga-toxin producing E. coli (STEC) with a confirmed or suspected link to leafy greens occurred in the U.S. between 2009 and 2017 – the contamination found as most likely to occur in the farm environment. As is discussed in an FDA Voices post, inspections were postponed to respond to industry’s request for more time to ensure that produce farmers had the training and information to comply with the new requirements, as well as to give the states more time to establish strong produce regulatory programs. So routine inspections for large farm were postponed until this spring, and for small farms (other than sprouts operations) until spring 2020. The reminder was also intended to provide farms with information on resources that are available to help in compliance efforts (which can be found in both the FDA Voices post and the Constituent Update). Like the agency’s initial Preventive Controls inspection, FDA states that “we’ll continue to educate while we regulate and look for knowledge gaps.” But also noting that the importance of PSR compliance “is underscored by the outbreaks of foodborne illness we’ve seen recently in fresh produce,” you can be certain that the inspections will be thorough and any “education” will be followed up as strictly as if it were an actual warning letter to “strengthen the safeguards and the confidence that consumers have in these products, which are vital to our well-being.” So, while it is clear that FDA will continue to focus on produce safety, I believe that it is imperative for any retailer or restaurant selling leafy greens to have a very robust supply chain control program for leafy greens. What this means is that you need to push your suppliers hard on what they are doing to control risks at the farm level. Water source is clearly a huge risk, and if nothing else, make sure you know all about the way growers you are sourcing from are controlling those risks. About The Acheson Group (TAG) Led by Former FDA Associate Commissioner for Foods Dr. David Acheson, TAG is a food safety consulting group that provides guidance and expertise worldwide for companies throughout the food supply chain. With in-depth industry knowledge combined with real-world experience, TAG’s team of food safety experts help companies more effectively mitigate risk, improve operational efficiencies, and ensure regulatory and standards compliance.


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