Scientist taking bacteria sample from agar plate

iStock, Manjurul

Pathogen That Plagues Food Processing Plants Eradicated by Blue Light

Using blue light over ultraviolet light presents less risk to the user

| 2 min read
Register for free to listen to this article
Listen with Speechify
0:00
2:00

WASHINGTON, DC — Blue light kills both dried cells and biofilms of the pathogen Listeria monocytogenes, a frequent contaminant of food processing facilities. Demise of L. monocytogenes occurred quickest when cells or biofilms were placed on polystyrene, a widely used, transparent form of plastic. The research is published in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

“These results contribute to advancing our understanding of the potential of blue light to treat inert surfaces contaminated with L. monocytogenes,” said corresponding author Francisco Diez-Gonzalez, PhD, Director and Professor, Center for Food Safety, University of Georgia. Although biofilms of pathogens are generally powerfully resistant to being exterminated, the results suggest that blue light could effectively destroy L. monocytogenes.

Want to stay up to date on the latest lab management news?

Subscribe to our free Lab Manager Monitor Newsletter.

Is the form not loading? If you use an ad blocker or browser privacy features, try turning them off and refresh the page.

In the study, the investigators deposited liquid suspensions of mixtures of five strains of L. monocytogenes on small, sterile rectangular plates made of six different materials, including polystyrene, stainless steel and silicone rubber, which were then allowed to dry. The investigators also used similar plates to grow biofilms, which they also allowed to dry.

Then, they shined blue light onto the biofilms and onto the dried suspensions of cells on the plates to determine the most effective combinations of doses and wavelengths, as well as the most effective surfaces on which to extirpate the pathogens.

“The application of blue light for controlling microbial contamination has the potential to offer an additional technology that could complement existing methods for disinfecting surfaces in contact with foods,” said Diez-Gonzalez, noting that blue light has been used for disinfection in hospitals. As compared to ultraviolet light, blue light offers reduced risk for the user, he said.

A post-doc in Diez-Gonzalez’ laboratory, Fereidoun Forghani, PhD, kick-started the investigation when—searching for new ideas—he came across the use of blue light as a potential antimicrobial intervention to sanitize surfaces. Forghani built some blue light prototypes and produced the first preliminary results treating pure cultures of Listeria.

- This press release was provided by the American Society for Microbiology

Loading Next Article...
Loading Next Article...

CURRENT ISSUE - January/February 2025

Energizing Leadership in Action

The science-backed behaviors that help leaders inspire thriving teams and organizations

Lab Manager January/February 2025 Cover Image