Silent Spoiler: Listeria Outbreak Raises Food Safety Concerns

LUNCH IS SERVED — As a multistate Listeria monocytogenes outbreak linked to deli meats raises concerns, researchers continue to work behind the scenes to ensure food safety standards. (U of A System Division of Agriculture photo by Nick Kordsmeier)

FAYETTEVILLE, Ark. — From deli counters to dinner tables, food safety relies on careful research and strict sanitation. As a multistate Listeria monocytogenes outbreak linked to deli meats raises concerns, researchers continue to work behind the scenes to ensure food safety standards.

Food safety scientists like Jennifer Acuff at the Arkansas Agricultural Experiment Station are dedicated to improving fresh and processed food safety and protecting food products from microbial contamination. Some of her work involves understanding how pathogens like listeria survive and spread — including in ready-to-eat foods.

“One of the things that my research program focuses on is trying to control environmental conditions so that pathogens are not welcomed guests into that environment,” Acuff said.

The U.S. Department of Agriculture’s Food Safety and Inspection Service is investigating a multistate outbreak of infections linked to Boar’s Head brand meats. So far, 7 million pounds of products have been recalled. The Centers for Disease Control and Prevention reported nine deaths and 57 hospitalizations from 18 states.

“Whenever we see Listeria monocytogenes outbreaks, we see high hospitalization rates and alarmingly high mortality rates. And that’s because listeria has this incredible ability to cause an invasive infection,” Acuff said.

Acuff said listeria is unique because it’s what scientists call a psychrotroph, meaning it can survive and grow at cold temperatures, unlike other foodborne pathogens such as Salmonella and E. coli.

This characteristic makes ready-to-eat foods like deli meats particularly vulnerable since they can remain in cold storage for extended periods. And listeria and other pathogenic bacteria, Acuff says, is particularly dangerous because it doesn’t visibly spoil food, unlike molds.

“We can’t see them on our food. There’s never an indicator to us that the food is spoiled by a pathogen,” she said. “Doing the sniff test or looking at it to see if it looks okay doesn’t tell you if listeria is there.”

Acuff is a Cooperative Extension Specialist and also a member of the Center for Food Safety, which conducts research and develops technologies to detect, control and reduce foodborne pathogens, toxins, and chemicals, enhancing food safety from production to consumption. The center is part of the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.

“These appointments give me really good opportunities to integrate the research findings we’re looking into with what is actually applicable to our stakeholders in Arkansas — producers, consumers and scientists alike,” she said.

Where does listeria come from?

Listeria is a ubiquitous bacterium, meaning it’s naturally present in the environment, Acuff said, and that contamination often signals a sanitation problem in food processing.

“When we see listeria associated with a ready-to-eat food product, it automatically sends up red flags because we don’t want to see it in the processing plant,” she said. “It is so easy to accidentally track it in, whether through workers’ boots or clothing, leaks in the environment, or even pests.”

The FSIS reported several noncompliance violations at a Boar’s Head plant in Virginia, including the visible presence of mold, trash and insects.

Mitigating risks

According to the CDC, symptoms of listeriosis, the illness caused by Listeria monocytogenes, can take up to 10 weeks to appear, making it difficult to promptly trace the infection’s source. Many people who are immunocompetent recover without medical care, so the actual number of cases is likely higher than reported. Immunocompromised individuals, such as pregnant people and those taking immunosuppressant drugs, are at particular risk, though.

Acuff said consumers can take steps to reduce their risk of listeria exposure. If you have any of the recalled products at home, throw them away immediately. It is also a good idea to clean any surface area the product might have encountered.

For general consumption, one effective prevention method is to heat deli meats to 165 degrees Fahrenheit, reducing the risk of listeria infections. Acuff also encourages consumers to be proactive about food safety when dining out, especially during an ongoing outbreak.

“People should feel empowered to ask a restaurant where their deli meat comes from. It’s okay to ask for more information,” she said.

While it’s impossible to produce food in a sterile environment, Acuff says it’s important to maintain strict sanitation standards to minimize risks.

“We don’t get to eat no-risk food,” she said. “So, being informed and knowing, ‘Am I willing to take this risk?’ is crucial.”

​To learn more about Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website. Follow on 𝕏 at @ArkAgResearch. To learn more about the Division of Agriculture, visit uada.edu. Follow us on 𝕏 at @AgInArk. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.

About the Division of Agriculture

The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.

The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on five system campuses.

The University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services without regard to race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an Affirmative Action/Equal Opportunity Employer.