A panel discussion at the Global Food Safety Conference about collaborative ways industry, academia and regulators may address listeria control quickly turned to a discussion about whole genome sequencing technology and what it may mean for the future of food safety.

Robert Tauxe, Ph.D., director of the division of foodborne, waterborne and environmental diseases at the Centers for Disease Control and Prevention in Atlanta, said that in 2013 the agency started a pilot project with the C.D.C. that used whole genome sequencing. He said the results showed there was more to be learned about listeria and more to be found.

“We are finding and solving more outbreaks, but finding them when they are smaller,” he said during the March 1 session.

Dr. Tauxe went on to note the use of whole genome sequencing at the C.D.C. will be expanded in 2018 to identify other such pathogens as salmonella, campylobacter and E. coli.

“Whole genome sequencing is a major step forward in outbreak detection and investigation,” he said.

The C.D.C.’s use of the technology may put food and beverage manufacturers in a bind, because regulators will have access to a more powerful technology to detect and trace outbreaks. A question arose during the panel session regarding how food manufacturers may use the technology, but not face greater regulatory scrutiny based on the findings.

Mickey Parish, senior science adviser for the Food and Drug Administration’s Center for Food Safety and Applied Nutrition, said the agency would encourage industry to adopt whole genome sequencing for their own internal purposes.

“We recognize they may want to take baby steps by looking at spoilage organisms initially to become more comfortable with the technology,” he said. “From there move toward the pathogen area.

“We are using it for regulatory purposes. Therefore a prudent firm might decide that if F.D.A. is using it in this way we need to use it to stay ahead.”

Matthew Stasiewicz, Ph.D., an assistant professor of food microbiology at the University of Illinois, Urbana-Champaign, said research he has conducted involving searching for and identifying the sources of 30 delis across the country said whole genome sequencing may improve the identification of persistent listeria monocytogenes in food environments.

“Whole genome sequencing can inform if a persistent strain is more likely,” he said. He added that the process may also help operators generate hypotheses about where the pathogen may be originating.

Dr. Parish added that the F.D.A. has created a council focused on whole genome sequencing to discuss the technology and its uses with industry stakeholders.

Back to listeria control

While the use of whole genome sequencing became a running theme throughout the session, speakers focused on the challenges faced by the food industry in reducing the incidence of the listeria pathogen.

“There is no one in the food industry who is not concerned about being hit by this,” said Anthony Huggett, vice-president and head of quality management for Nestle S.A., Vevey, Switzerland. “All food sectors are hit by this and an industry-wide response is necessary.”

Dr. Tauxe said approximately 800 cases of listeriosis occur in the United States each year, that almost all who are infected are hospitalized and an estimated 16% die. Key foods identified as sources include raw milk, soft cheeses and mung bean sprouts. Recently such novel foods as caramel dipped apples and ice cream have been implicated in outbreaks.

One industry group that has had success in controlling listeria is processed meats manufacturers. John Butts, Ph.D., vice-president of research for the processed meats manufacturer Land O’ Frost, Munster, Ind., and president of Food Safety by Design, a consultancy, said processed meat companies have been measured for listeria by the U.S. Department of Agriculture’s Food Safety and Inspection Service for the past 25 years and, over time, the per cent of positive results have declined.

“It’s this simple,” he said. “Eliminate the residents, control transfer of the organism and deploy process management techniques.”

Best practices he said have proven essential to listeria control in the meat industry include having clean, dry floors that do not have cracks. Equipment should require one tool or no tools for disassembly to be cleaned. Cleaning-out-of-place should be used for small parts, equipment sub-assemblies, and hand tools. Heat intervention should be used on large equipment.

“I started cooking slicers in 1998,” he said.

Companies should also consider the installation of critical air handling systems.

“They cost us twice as much, but we got a great return,” he said.

The ceiling space above processing areas must be considered as well as the separation of raw and ready-to-eat raw materials.

“I’m not talking about a yellow line on the floor,” he said. “There needs to be actual separation.”

Donna Garren, Ph.D., senior vice-president of regulatory and technical affairs for the American Frozen Food Institute, McLean, Va., emphasized that when the processed meat industry came together to work on the issue they saw the number of listeria incidents decline.

“This is a global issue and we all need to work together,” she said.