Watch Out! Pathogens Continue to Emerge and Reemerge ... and It’s Not Just FDA Using WGS to Track
Updated: Nov 18, 2018
Listeria in frozen corn in Europe; Salmonella linked to dried coconut in eight U.S. states. We continue to see pathogens causing outbreaks in foods not generally associated with them. And while all ready-to-eat (RTE) foods – such as dried coconut – may be a more obvious area for caution and preventive controls, today’s cooks are often using foods not generally considered to be RTE – such as frozen corn – without further cooking.
Take, for example, the online recipe for salsa just like Chipotle’s, which calls for “frozen sweet yellow corn, defrosted and drained.” Had a recipe-clipper used the frozen corn which is considered to be the likely source of the Listeria monocytogenes outbreak affecting Austria, Denmark, Finland, Sweden, and the UK, the result could be at least one more statistic to add to the 32 reported cases, including six deaths, as published by EFSA and the European Centre for Disease Prevention and Control (ECDC) March 8.
It’s not the first time that either dried coconut or frozen vegetables have been implicated in an outbreak, but these foods are not always the first ones you think of when conducting a risk assessment for high-risk foods. Nor are they foods that their manufacturers would want to see on FDA’s eventual high-risk foods list, which FSMA requires the agency to develop – and will require additional recordkeeping for those manufacturers. So, perhaps both products should be set a bit higher in food manufacturers’ risk assessments.
These two outbreaks also have significance in that they show the increased use of whole genome sequencing (WGS) by governments outside the U.S. as well as by FDA. As the EFSA write-up notes, “Whole genome sequencing was used to define the multi-country outbreak of L. monocytogenes serogroup IVb, multi-locus sequence type 6 and to identify the implicated food source.” And the CDC coconut Salmonella report similarly states, “WGS performed on bacteria isolated from ill people showed that they were closely relatedly genetically.” In fact, it was CDC that notified FDA about a Salmonella Typhimurium cluster which was detected by PulseNet.
In the coconut-implicated outbreak, for which FDA’s investigation is ongoing, 13 cases in eight states have been reported thus far with three hospitalizations and no deaths, and recalls have been made on coconut from Vitamin Cottage Natural Food Markets and International Harvest. In Europe, the Listeria investigations have pointed towards frozen corn packed in Poland and processed and produced in Hungary, with further investigation recommended to identify the exact point of contamination in the food chain. Additionally, EFSA’s report notes that new cases may still be identified due to the long incubation period of listeriosis, the long shelf-life of frozen corn products, and the potential consumption of frozen corn bought before the recall was implemented.
Foodborne illness-causing pathogens can be very adaptive, not only tolerating and surviving some minimal processing techniques (as the frozen vegetable outbreaks show), but even increasing their resistance in some cases. Additionally, as described in Emerging and Reemerging Foodborne Pathogens, foodborne diseases can increase due to changes in microorganisms and in the human population and lifestyle; the globalization of the food supply; and the inadvertent introduction of pathogens into new geographic areas.
Because of such factors, foodborne pathogens and the associated diseases will continue to emerge, reemerge, and adapt, and the food industry needs to continue to stay a jump ahead – monitoring for any indicators and evidence, taking corrective action quickly and conducting root-cause analysis when positives are found, and ensuring that all processes and practices are based on the latest science- and risk-based information available.
So what does all this mean? From my perspective we need to continue to pay close attention to consumer behaviors in terms of the way in which consumers handle foods and don’t always cook them. We need to recognize new vehicles for foodborne pathogens that become linked to outbreaks and constantly stay vigilant to change in the world of microbiological risks.
As the famous line from Michael Crichton’s Jurassic Park states, “Life finds a way.” Pathogenic bacteria are alive and continue to find ways to survive.
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. www.AchesonGroup.com