Time-course study of the antibacterial activity of an amorphous SiOxCyHz coating certified for food contact

: One of the most-used food contact materials is stainless steel (AISI 304L or AISI 316L),owing to its high mechanical strength, cleanability, and corrosion resistance. However, due to thepresence of minimal crevices, stainless-steel is subject to microbial contamination with consequentsignificant reverb on health and industry costs due to the lack of effective reliability of sanitizingagents and procedures. In this study, we evaluated the noncytotoxic effect of an amorphous SiOxCyHzcoating deposited on stainless-steel disks and performed a time-course evaluation for four Gramnegative bacteria and four Gram-positive bacteria. A low cytotoxicity of the SiOxCyHz coating wasobserved; moreover, except for some samples, a five-logarithm decrease was visible after 1 h on coatedsurfaces without any sanitizing treatment and inoculated with Gram-negative and Gram-positivebacteria. Conversely, a complete bacterial removal was observed after 30 s-1 min application ofalcohol and already after 15 s under UVC irradiation against both bacterial groups. Moreover, coatingdeposition changed the wetting behaviors of treated samples, with contact angles increasing from90.25oto 113.73o, realizing a transformation from hydrophilicity to hydrophobicity, with tremendousrepercussions in various technological applications, including the food industry.