Investigation into the antibacterial activity of silver, zinc oxide and copper oxide nanoparticles against poultry-relevant isolates of Salmonella and Campylobacter

Nanotechnology is currently contributing substantially to the development of a broad range of innovative technologies in the agricultural, feed and food sector. To date, very little work has been done to investigate the efficacy of antimicrobial nanoparticles against the pathogens of highest concern to the poultry industry. This study is the first to report on the effectiveness of CuO nanoparticles against Salmonella and on the effectiveness of Ag and CuO nanoparticles against Campylobacter. The aim of this study was to assess the in vitro activity of silver (Ag), zinc oxide (ZnO) and copper oxide (CuO) nanoparticles against Salmonella and Campylobacter isolated from poultry. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by a broth microdilution method in 96 well plates. The MIC for all Campylobacter strains was in the order of Au ≥ CuO ≥ ZnO nanoparticles. Ag nanoparticles were the most effective against Salmonella. The growth kinetics of the Salmonella strains were also assessed during exposure to nanoparticles in liquid media. Growth was dependant on NP concentration with some differences noted between strains. While these specific size nanoparticles are effective against pure cultures of bacteria the antimicrobial effectiveness of the nanoparticles should be further examined under industry-relevant conditions.