Pulsed Light inactivation of Listeria innocua on food packaging materials of different surface roughness and reflectivity

Inactivation of Listeria innocua on food packaging materials by Pulsed Light (PL) treatment was investigated. Coupons of low density polyethylene (LDPE), high density polyethylene (HOPE), polyethylene-laminated ultra-metalized polyethylene terephthalate (MET), polyethylene-coated paperboard (TR), and polyethylene-coated aluminum foil paperboard laminate (EP) were inoculated with L innocua cells in stationary growth phase. Inoculated courions (similar to 8 CFU/coupon) were treated with Pulsed Light fluence of up to 8.0 J/cm(2), and survivors were determined. Reductions up to 7.2 +/- 0.29, 7.1 +/- 0.06, 4.4 +/- 0.85, 4.5 +/- 1.32, and 3.5 +/- 0.82 log CFU/coupon were obtained on LOPE, HOPE, MET, TR, and EP, respectively. Inactivation data were used to determine Weibull kinetic parameters and predict inactivation in a wide range of fluence. Increasing surface reflectivity and surface roughness appeared to induce lower inactivation, Minimal surface heating was observed for all materials except MET, on which significant heating occurred. These results demonstrate the potential of Pulsed Light as an effective method for decontaminating food packaging materials. (C) 2012 Published by Elsevier Ltd.