Nonthermal sterilization of Listeria monocytogenes in infant foods by intense pulsed-light treatment

The purposes of this study were to determine the inactivation effects of intense pulsed light (IPL) on Listeria monocytogenes and the commercial feasibility of this sterilization method. The inactivation of L. monocytogenes at cultivated plates increased with increasing electric power and treatment time. Approximately 4-5 log reduction of the cell was achieved with IPL treatment for 5000, 600, 300, and 100 μs at 10, 15, 20, and 25 kV of voltage pulse, respectively. In the early stages of IPL treatments at 10, 15, and 20 kV, little inactivation was observed with a critical treatment time (t_c) of 360.6, 95.5, and 32.2 μs, respectively, while an abrupt inactivation without a critical treatment time was observed at 25 kV. The sterilization effects on commercial infant foods inoculated with L. monocytogenes were investigated at 15 kV, which showed higher energy efficiency for the inactivation of L. monocytogenes.