Intense pulsed light (IPL) and UV-C treatments for inactivating Listeria monocytogenes on solid medium and seafoods

The inactivation effects of intense pulsed light (IPL) on Listeria monocytogenes surface-inoculated on solid medium and on seafoods such as flatfish, salmon, and shrimp fillets were investigated for various light doses (0.11–1.75mJ/cm2 per pulse), number of pulses (0–9800 pulses, treatment time of 0–1960s), and total fluences (0–17.2J/cm2), and also the inactivation characteristics of UV-C irradiation on L. monocytogenes were evaluated for treatment time of 0–1960s. Besides, any structural damage to the treated cells after IPL and UV-C treatments was evaluated by transmission electron microscopy (TEM). On the solid medium, approximately 4.0- and 6.0-log reductions of L. monocytogenes cells were achieved with UV-C irradiation for 1000s and with IPL treatment for 180s (900 pulses) at a fluence of 1.75mJ/cm2 per pulse, respectively, with a negligible temperature rise (