Evaluation of pulsed xenon UV irradiation on inactivation of Listeria monocytogenes on stainless-steel surfaces

UV-C disinfection is a safe and effective method for the inactivation of bacteria, viruses, spores, and other microorganisms. Pulsed xenon UV lamps (PX-UV) can provide high intensity UV-C irradiation in a short time. To improve our understanding of which factors affect the disinfection efficacy of PX-UV lamps, a rigorous investigation of the effects of exposure time, frequency, UV fluence, and angle of irradiance on log reduction of Listeria monocytogenes on stainless steel surfaces was characterized. Total UV fluence received proved to be the main determinant of log reduction regardless of pulse frequency, angle, or exposure time. However, 30 s of exposure to UV light at 25 Hz resulted in a 5.59-log reduction which corresponds to a fluence of 151.2 mJ/cm2. Kinetic constants of UV inactivation was determined to allow end users to calculate the required fluence needed to achieve the desired log-reduction. This work confirms that UV-C fluence should be the primary consideration when deploying PX-UV lamps as a no-touch disinfection technology and that operational parameters should be selected to achieve the desired fluence. •A 5.59-log reduction in Listeria monocytogenes on stainless steel surfaces was achieved at 25 Hz for 30s (151.2 mJ/cm2).•The highest dose/pulse was at 5 Hz at 0.32 ± 0.01 mJ/cm2/pulse and decreased to 0.23 ± 0.02 mJ/cm2/pulse at 25 Hz.•The single most important factor for effective inactivation of L. monocytogenes was total germicidal UV dosage.•Inactivation kinetics of pulse-xenon UV light on L. monocytogenes on stainless steel surfaces showed two stage decay.