Influence of surface properties of produce and food contact surfaces on the efficacy of chlorine dioxide gas for the inactivation of foodborne pathogens

The objective of this study was to evaluate the influence of surface properties of produce and food contact surfaces on the antimicrobial effect of chlorine dioxide (ClO2) gas against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. The hydrophobicity of the selected surfaces was evaluated by water contact angle measurements. White light scanning interferometry (WLSI) was used to acquire surface roughness values of each surface. Produce and food contact surfaces inoculated with foodborne pathogens were treated with 20 ppmv ClO2 gas for 5, 10, and 15 min. As treatment time increased, different levels of inactivation of the three pathogens were observed among the samples. Contact angles of produce and food contact surfaces were highly and negatively correlated with the log reduction of all three pathogens. There were generally weaker correlations between the roughness values of sample surfaces and microbial reduction compared to those between hydrophobicity and microbial reduction. The results of this study showed that surface hydrophobicity is a more important factor relative to bacterial inactivation by ClO2 gas from the surface than is surface roughness. Also, the existence of crevices with features of similar size to the pathogen cell was more important than the R-a and R-q values in the inactivation of pathogens. (C) 2017 Published by Elsevier Ltd.