Development and Evaluation of Silver Zeolite Antifouling Coatings on Stainless Steel for Food Contact Surfaces

The majority of foodborne illness outbreaks can be linked to cross-contamination events through contact with contaminated surfaces. Consequently, there is a sustained interest in developing antimicrobial coatings such as silver zeolite to reduce contamination levels. In this study, we examined the efficacy of silver zeolite for preventing biofilm formation by common foodborne pathogens such as Listeria innocuaSeeliger and Escherichia coliO157:H7. Biofilm formation was assessed by cresyl violet assay, quantification of colony-forming units and scanning electron microscopy, and atomic force microscopy. For silver zeolite suspended in growth media, concentrations of 0.3% w/v were effective at reducing bacterial growth of L.innocua after 8h. For E.coli incubated with silver zeolite, there was a dose-dependent reduction in bacteria after 4h. When coated stainless steel coupons were incubated with Listeria and E.coli, significant reductions in bacterial growth were achieved. Coating stainless steel food processing surfaces with silver zeolite may provide a means of reducing cross-contamination events of pathogens and spoilage microbes. The ability of the surface to resist the attachment of biofilms provides a complementary approach to chemical sanitation. Practical ApplicationsAntimicrobial coatings are gaining importance for the food manufacturing and food processing industries for food safety applications. The results of this study demonstrate that the silver zeolite could inhibit foodborne pathogenic biofilm formation and could potentially serve as an effective antimicrobial coating for food contact surfaces. The methodology for impregnating the silver zeolite in polymers followed by coating on stainless steel surface provides detailed procedure for preparing the antimicrobial surfaces.