Nano-enabled Control of A. flavus and F. proliferatum: inhibition of fungal growth and mycotoxin biosynthesis by zinc oxide nanoparticles

Abstract Recently, zinc oxide nanoparticles (ZnO-NPs) have been proposed as more sustainable substitutes for chemical fungicides; however, their potential in fungicidal and mycotoxin biosynthesis control in food-related pathogens is still under research. In this study, we synthesized and characterized ZnO-NPs with a high degree of crystallinity and antifungal and antimycotoxigenic properties against two significant toxigenic fungi, Aspergillus flavus f10 and Fusarium proliferatum f30, by using a combination of microwave-assisted combustion. X-ray diffraction (XRD) and FTIR analyses confirmed the formation of a hexagonal wurtzite phase, while TEM imaging revealed rod-like ZnO nanostructures with diameters of approximately 70–90 nm and lengths extending up to approximately 700 nm. ZnO-NPs demonstrated high concentration-dependent fungicidal behavior; 150 ppm decreased the growth of A. flavus and F. proliferatum by 75 and 97%, respectively whereas bulk zinc sulfate had no effect. SEM revealed severe morphological damage, such as hyphal shrinkage, disturbed sporulation, and outgrowths. ZnO-NPs nearly completely inhibited aflatoxin biosynthesis (reduced AFB 1 and AFG 2 by 99-99.9) and partially, but significantly inhibited fumonisin B 1 synthesis (reduced by approximately 85%), as confirmed by HPLC-analysis. These findings suggest that ZnO-NPs are an effective nanobased intervention to counter the development of fungal contamination and mycotoxin build-up in maize and other food systems. ZnO-NPs offer a promising platform for improving food safety, minimizing post-harvest losses, and promoting sustainable agriculture by simultaneously addressing the proliferation of pathogens and the production of toxins.