One University of Georgia (UGA) research project in 2021 will be aimed at protecting produce packing plants from Listeria, according to Francisco Diez, Director and Professor at the UGA Center for Food Safety in Griffin, Georgia.
The lead investigator is Diez. The grant project is funded by the Center for Produce Safety and covers the entire 2021 year. His objective will be to see if the antimicrobial blue light, which has shown antimicrobial effects and is considered safe for humans, can kill the Listeria monocytogenes.
“It’s been found by a number of reports that blue light can be lethal for some bacteria. There’s been applications of blue light in some settings like hospitals in which they can leave the blue light on and eventually that protects if there’s any presence of bacteria on the surface in the room; on floors, on walls or other materials,” Diez said. “What we’re trying to address in this proposal is under simulated conditions in the laboratory that will resemble surfaces that would be found in a packing plant is whether we can kill Listeria monocytogenes.”
According to the award description, Listeria monocytogenes as dried cells or biofilms will be placed on a wide range of surfaces (stainless steel, plastic, etc.) and exposed to blue light to evaluate its antimicrobial efficacy.
Diez stresses that this research would not replace the normal sanitizing and cleaning procedures that are already in place at packing plants across the Southeast. Blue light would be used only as a supplement. It could really be useful in case a piece of equipment or spot on a wall or floor was missed and was left exposed to the Listeria pathogen.
“Listeria is not so easy to control. Most treatments can kill listeria. A good sanitizing program with a combination of good cleaning and sanitizing may control listeria in most cases but the organism is so capable of surviving that it can remain on surfaces or equipment, in small niches and crannies,” Diez said. “If a piece of equipment has a little corner that didn’t get cleaned or sanitized properly and gets in contact with vegetables, either packing or cutting or cleaning, then (the bacteria) could get into the product.”
What is Listeria?
Listeria is one of the major food-borne pathogens that is extremely dangerous if consumed.
“Fortunately, it doesn’t cause as many cases per year as salmonella. But we’re very concerned because Listeria Monocytogenes has a relatively high death rate. About 20% of people that contract Listeria, they die or they develop serious conditions,” he said. “Listeria is a very pervasive organism in nature. It’s found in many, many natural environments. Plants or plant tissues could be colonized by Listeria.”