A recent study published in Applied and Environmental Microbiology has demonstrated the efficacy of antimicrobial blue light technology in the inactivation of both dried cells and biofilms of Listeria monocytogenes. The pathogen was inactivated most rapidly when placed on polystyrene, a widely used type of plastic.
To assess the performance of blue light against L. monocytogenes, the researchers deposited liquid suspensions of mixtures of five strains of the pathogen (one human isolate, one sheep isolate, two coleslaw isolates, and one isolate from a cantaloupe outbreak) on sterile plates made of different materials commonly used in food production environments, specifically: polystyrene, stainless steel, polyvinyl chloride (PVC), silicone rubber, and high-density polyethylene (HDPE). The pathogen cells were allowed to dry on the plates. The researchers also used similar plates to grow biofilms, which they also allowed to dry.