Cold atmospheric pressure plasma for the sanitation of conveyor belt materials: Decontamination efficacy against adherent bacteria and biofilms of Escherichia coli and effect on surface properties

The inactivation efficacy of a cold atmospheric pressure plasma jet against Escherichia coli DH5 alpha adherent cells and biofilms on two conveyor belt materials was evaluated. A 120 s treatment time with a 3 cm treatment distance from the surface reduced both adherent cells (initial 5.6 +/- 0.2 log CFU/coupon) and 24 h biofilms (initial 5.8 +/- 0.4 log CFU/coupon) on stainless steel (SS) by >4.6 log CFU. While the same treatment reduced adherent cells (initial 5.7 +/- 0.5 log CFU/coupon) and 24 h biofilms (initial 6.9 +/- 0.5 log CFU/coupon) on polyvinyl chloride (PVC) by 3.8 +/- 0.9 and 3.5 +/- 0.5 log CFU, respectively. Mature biofilms (72 h grown) were more resistant than 24 h grown biofilms. Lower microbial reductions were observed on scratched surfaces compared to intact ones. No changes were observed in SS and PVC surfaces in terms of chemical properties and visual topography. CAPP is a promising waterless technique for the sanitation of metallic and polymeric conveyor belt surfaces.Industry relevance: Cold atmospheric pressure plasma (CAPP) has the potential as waterless technology to inac-tivate bacteria and their biofilms on food contact surfaces without affecting the material properties and the visual topography. CAPP can be integrated for industrial operation by mounting a CAPP jet on a robotic arm or moving a conveyor belt under a stationary CAPP jet for surface sanitation. This environmental-friendly and residue-free nature technology can be useful in the food industry.