WOODLAND, CA - The Center for Produce Safety’s (CPS) 2021 Research Symposium is quickly approaching, set to take place on June 29 from 10 a.m. to 12 p.m. PDT. Dr. Martin Wiedmann, Ph.D., Gellert Family Professor of Food Safety at Cornell University, will be presenting his research results at the event, focusing on how produce facilities can identify and manage resident strains of the foodborne pathogen, Listeria monocytogenes, dubbing the efforts as “seek and destroy” missions.

“Every processing facility is different, and oftentimes the interventions are expensive,” Wiedmann said in a press release. “The seek part is time consuming, but once you’ve trained people, you can, with a reasonable budget, find issues. Once you’ve identified interventions, whether they address design issues or maintenance or even cracks in a floor, it’s sometimes a capital investment with no certainty it will really fix the issue.”

Over the years, the produce industry has significantly improved its ability to detect or seek out persistent Listeria strains, said Wiedmann. Where the industry often remains challenged is in the “destroy” part of the mission. As a result, Wiedmann said the industry needs improved resources to rapidly pinpoint factors that may contribute to Listeria persistence and then identify appropriate science-based interventions to prevent, eliminate, or manage relevant causes.

“Factors affecting persistence of Listeria monocytogenes need to be identified for evaluation and prioritization of interventions,” Wiedmann said, noting that he and his team plan to take a three-step approach that will ultimately result in a decision support tool.

Joining Wiedmann as co-principal investigator is Renata Ivanek, Ph.D., also with Cornell, who has expertise in developing computer-based models. Their project began with a literature search that expanded beyond just produce-related situations, since Listeria persistence can also be a problem elsewhere. In addition, they looked at both published and unpublished writeups.

“The idea is there will be useful experiences in the produce industry already and in other industries that could be helpful for the produce industry with the destroy part of it,” Wiedmann said. “Field trials can be expensive and difficult. But if there is existing knowledge, we want to take advantage of it.”

After winnowing the original 1,656 documents down to 264, the team further screened them to identify about 32 of the most relevant strategies. They then validated some interventions identified with four cooperating packinghouse facilities. Initially, they sampled each facility before any interventions and performed a formal root cause analysis with facility personnel.

Based on those results, the researchers developed a step-by-step approach packinghouses can use to conduct a root cause analysis to identify the most likely factors behind specific persistence as well as appropriate interventions.

Wiedmann said it was “absolutely essential” to have this type of produce-industry participation to ensure their results were applicable to produce facilities. “To figure out what’s happening in the real world, we need to be in a real facility,” he said.

Interventions they identified but were too difficult to validate experimentally in a packing facility were tested by using a previously developed computer model.

“We’ve re-created produce facilities in almost 3D, so we can identify places where Listeria can survive over time and we can see what happens as we change things,” Wiedmann said.

In the end, the researchers plan to develop a decision-support tool the industry can use to develop intervention strategies. Much like they did when they were validating interventions, the researchers will seek industry input on the support tool from a focus group. The tool also will allow plant personnel to run “what if” scenarios to compare different strategies, but it won’t replace the human element.

For more information on the event and to register, please click here.

Center for Produce Safety