Inactivation of Listeria monocytogenes on ready-to-eat food processing equipment by chlorine dioxide gas

The effectiveness of chlorine dioxide (ClO2) gas to control Listeria contamination on food contact and environmental surfaces was investigated in order to comply with the zero tolerance policy. Different ClO2 gas concentrations (0.3, 0.5, 1 and 2 mg/l) were evaluated in order to inactivate Listeria monocytogenes (planktonic cells and biofilms) on stainless steel coupons. An ideal condition was then selected, and its applicability was studied on a commercial meat slicer and an industrial hot-dog peeler (using a surrogate organism). L. monocytogenes biofilm cells initially showed more sensitivity to ClO2 treatments, as compared to planktonic cells, but after 10 min, ∼4 log CFU/cm2 reduction was observed for all the concentrations used. The treatment at 2 mg/l for 30 min was selected for the further validation study. Complete pathogen inactivation, >5 log CFU/cm2, was obtained on both the meat slicer and peeler, demonstrating the potential applicability of ClO2 gas as a sanitizing agent for RTE meat processing equipment.