Resistance of Multispecies Biofilms to Sanitization with Chlorine, Peroxyacetic Acid, and Ozone Nano-bubble−Activated Water

• The impact of chlorine, peracetic acid and ozone on biofilms was determined. • Sanitisers were used to treat 12 multi-species biofilms. • The biomass of biofilms formed at 4 °C was higher when compared to 25 °C. • Sanitisers differentially impacted multi-species biofilms. • None of the biofilms resisted all three sanitisers. Microbial communities that permanently persist in food processing facilities challenge food safety and food quality. Sanitization resistance is enhanced by the formation of biofilms but sanitization resistance in multi-species biofilms remains poorly documented. It was therefore the objective of this study to determine the resistance of biofilms formed by 12 microbial communities to 200 ppm chlorine, 40 ppm peracetic acid and nano-bubbles with 7 ppm ozone. The composition of the microbial communities was analyzed by culture and by 16S rRNA gene amplicon sequencing. The microbial communities, previously isolated from a pork processing facility, consisted of 6 – 19 bacterial strains each and together comprised 130 strains representing 19 genera. All 12 communities formed dense biofilms at 4 °C and, to a lesser extent ( P