Effects of 405-nm LED Treatment on the Resistance of to Subsequent Environmental Stresses.

can persist under a wide range of stress conditions, contributing to its ubiquitous distribution and unique pathogenic traits. Light from light-emitting diodes (LEDs) has recently been shown to inactivate various pathogens. Thus, the aim of the present study was to evaluate the effects of light treatment using a 405-nm LED on the subsequent resistance of to environmental stresses, including oxidative stress, ultraviolet (UV) irradiation, low temperature, osmotic pressure, simulated gastric fluid (SGF), and bile salts. Following 405-nm LED illumination at 4°C for 150 min, the survival of was examined after exposure to oxidative stress (0.04% HO), UV irradiation (253.7 nm), low temperature (4°C), osmotic pressure (10, 15, or 20% NaCl), SGF (pH 2.5), or bile salts (2%). The mechanisms responsible for changes in stress tolerance were identified by assessing the transcriptional responses and membrane integrity of . The 405-nm LED treatment reduced the resistance of to all the stresses tested. Reverse transcription quantitative real-time polymerase chain reaction analysis indicated that the transcription of multiple genes associated with stress resistance, including , , , , , and , was reduced by 405-nm LED. Confocal laser scanning microscopy revealed that 405-nm LED treatment disrupted the integrity of the cell membrane compared with untreated bacteria. Therefore, 405-nm LED illumination appears to reduce the resistance of to various stress conditions. These findings suggest that 405-nm LED treatment could be used to effectively prevent and/or control with contamination along the entire food-processing chain, from production to consumption.