Antimicrobial ecological waterborne paint based on novel hybrid nanoparticles of zinc oxide partially coated with silver

•Evaluation of antimicrobial activity against bacteria and molds of ZnO-Ag nanopowders.•Antimicrobial activity of a waterborne paint formulated with ZnO-Ag NPs in plastic surfaces against bacteria and molds.•Pseudomonas aeruginosa was the most resistant followed by S. aureus, L. monocytogenes, S. senftenberg, B. subtilis and A. niger.•Effect of antimicrobial activity was slightly reduced due to aging and leaching process of ZnO-Ag NPs waterborne paint.•Ecological waterborne paint for indoor use with a VOC less than 100 ppm. Antimicrobial activity of Zinc oxide partially coated with silver nanoparticles produced by Flame Spray Pyrolysis (FSP) as an additive to include in waterborne paints with promising applications in areas as schools, clinics or hospital environments and in food industry equipment and facilities has been demonstrated. Due to the current increase of multi-resistant microorganisms, the results obtained in this research would enable an enhanced sanitary conditions to avoid health problems of professionals and improve the Hazard Analysis Critical Control Point (HACCP) in the Food Industry like a way to control the biofilm formation on surfaces and beyond. The nanomaterial was prepared by the use of Flame Spray Pyrolysis process obtaining nanoparticles of about 35 nm coated with ca. 5% (w/w) of silver (Ag). Antimicrobial trials showed that these ZnO-Ag nanoparticles has a potential effect against different bacteria (Staphylococcus aureus, Pseudomona spp, Salmonella spp, Bacillus subtilis, Listeria monocytogenes) and molds as Aspergillus niger. Furthermore, these nanoparticles were evaluated as an antimicrobial waterborne paints additive, and formulations with 0,15% (w/w) showed >5 mm inhibition zone against the main bacteria and molds tested.