Ask any scientist who studies foodborne illnesses to name the bacteria, virus or parasite that causes them the most sleepless nights, and near the top of their list will be these two scary words: listeria monocytogenes.

Present in soil and water, the bacteria called listeria wreaks a kind of havoc that goes well beyond the garden-variety “I think I ate some bad potato salad” illness that all of us have experienced at one time or another. What starts as flu-like symptoms up to a month after ingesting it can progress to confusion, loss of balance and convulsions as the listeriosis infection spreads throughout the body. According to the Centers for Disease Control and Prevention, listeria is the third leading cause of food poisoning-related deaths in the U.S., killing about 260 of the roughly 1,600 people who ingest it. It’s especially deadly for newborns, the elderly and people with compromised immune systems.

In 2020, for example, deli meat containing listeria infected a dozen people in Florida, Louisiana, Massachusetts and New York. All 12 were hospitalized, and one died.

Leonard Williams, Ph.D., from the College of Agriculture and Environmental Sciences doesn’t want you or anyone else to get listeriosis. In fact, he and his colleagues are spending quite a bit of time figuring out ways to keep you safe from it.

Williams is director and professor of food safety and microbiology at N.C. A&T’s Center for Excellence in Post-Harvest Technologies on the North Carolina Research Campus in Kannapolis. He and one of his doctoral students, Akbar Bahrami, are joining researchers in the U.S. and abroad to consider the impact that antimicrobial compounds could have on protecting consumers from listeria. 

The work was funded in part by a grant from the U.S. Department of Agriculture’s National Institute for Food and Agriculture.

The research, now in its early stages, eventually will explore how to achieve this through encapsulated technologies, which in this situation means embedding antimicrobials directly into the food or the packaging. The process makes use of nanoscience, the use of ultra-small particles to enhance properties.

Food companies have been using microencapsulation or nanoencapsulation for years to add flavor, aroma or even nutritional value to foods. And food scientists have tried various methods over the years to control the growth of listeria in food — including sterilization, which can change the way the food looks or tastes; and heat, which can’t be used on fresh fruits and vegetables.

Using encapsulated technologies to combat listeria is something new. It also has the potential to save lives.

“This is a very, very long-term project, and there are so many avenues that we’re going to explore,” said Williams, a Greensboro native and graduate of Smith High School. “Before we actually go deep into the nanoscience, we have to know how the actual strains (of listeria) respond to those antimicrobials.”

Testing for pathogens

So first things first: Williams’ team had to go grocery shopping.

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