Antimicrobial effect of ZnO nanoparticles synthesized by different methods against food borne pathogens and phytopathogens

Abstract Phytopathogens and food-borne pathogens are a major threat to human health, so there is an urgent need to find some alternatives to overcome these issues. Nanomaterials have shown great potential as antimicrobials therefore, in this study, ZnO nanoparticles were synthesized using Azadirachta indica leaf extract and studied for their antimicrobial activity. Their antimicrobial efficacy was studied against phyto and food borne pathogens and compared with the commercially available chemically synthesized ZnO nanoparticles (Chem-ZnO-NPs). The Azadirachta indica synthesized ZnO-NPs were characterized using UV–VIS spectroscopy, DLS, and FTIR. DLS data depicts that the size of nanoparticles in colloidal solution is approximately 96 nm, with polydispersity index (PDI) of 0.37. The antimicrobial activity was studied using pour plate method. The MIC data for food borne pathogens (E. coli and S. aureus) shows that Azadirachta indica mediated ZnO-NP are more efficient as compared to Chem-ZnO-NPs. For phytopathogens (Alternaria alternata, Sclerotium rolfsii and Stemphylium solani) also the result shows that Azadirachta indica mediated ZnO-NP exhibit more efficient antifungal properties. Therefore, the synthesized ZnO-NP can be efficiently used in place of commercially available fungal pesticides.