Research examines challenges in packinghouse sanitation

It’s no secret Listeria monocytogenes is the enemy of produce packinghouses. The Centers for Disease Control and Prevention estimates about 1,600 people in the U.S. get sick, and about 260 people die from listeriosis.

Research at Penn State University looks at the challenges facing produce packinghouses when trying to eradicate foodborne pathogens — and the results might seem a bit surprising.

Jasna Kovac, associate professor of food science and a professor of food safety at the university, says listeria can grow at temperatures similar to the human body but also at low temperatures found in food processing facilities and refrigerated food storage.

“This means that if listeria ends up in a food processing environment like fruit packing facilities, it's going to be able to grow on environmental surfaces if there's nutrients present to support its growth,” Kovac said in this episode of the "Tip of the Iceberg" podcast.

Kovac says through her research, she learned that biofilms — bacteria that attach to surfaces — can unintentionally protect listeria and other foodborne pathogens in packing facilities. Biofilms form on top of the listeria and enclose it, which makes cleaning and sanitizing efforts more challenging in packinghouses.

“Our research has shown that, for example, if you have free-floating listeria, using a sanitizer called benzalkonium chloride would kill 99.9% of these cells in two hours,” she said. “[When] we expose biofilms made of listeria to this sanitizer, we barely see any killing of listeria, so that just shows us how problematic these biofilms are and how they affect our ability to control listeria in processing facilities.”

She says this is why cleaning processes are critical to ensure that biofilms do not form from organic matter and sanitizer has a surface free from protectant biofilms to kill foodborne pathogens. Packing facilities need to prioritize the training of staff working in the facility to understand the risks of improper cleaning and sanitizing.

“Investments into training and education of the management and employees working on the ground are extremely important for building a culture of food safety which is so important for prioritizing best practices for food safety.”

Listen to the conversation using the podcast player embedded above or by clicking here.