Biogenic synthesis of Ag/AgCl nanoparticles from Schinus molle ethanolic extracts: evaluation of their antibacterial and antifungal activity against broccoli pathogens

Fruits and vegetables are common sources of foodborne illnesses and are susceptible to deterioration after harvest due to physiological changes and the presence of pathogenic microorganisms. Broccoli (Brassica oleracea var. italica) is a crop of commercial and nutritional relevance; however, flower rot occurring in the field and during postharvest handling can affect its quality and yield. In Mexico, this condition has been associated with the phytopathogens Fusarium oxysporum, Fusarium verticillioides, and Alternaria alternata. This context highlights the need to explore alternatives to lessen the impact of these microorganisms, including the use of nanoparticles with antimicrobial properties. In this study, silver/silver chloride nanoparticles (Ag/AgClNPs) were synthesized using an ethanolic extract of Schinus molle leaves. The resulting nanomaterial exhibited quasi-spherical morphology and polydisperse particle sizes ranging from 6 to 93 nm. The Ag/AgClNPs showed antibacterial activity against Escherichia coli, Salmonella agona, Salmonella infantis, Staphylococcus aureus, Bacillus cereus, and Pseudomonas spp., with minimum inhibitory concentrations (MICs) of 8, 64, 32, 32, 64, and 64 μg/mL, respectively. The nanoparticles also inhibited the in vitro mycelial growth of Alternaria alternata, Fusarium oxysporum, and Fusarium verticillioides, with species-dependent efficacy and maximum inhibition values of approximately 69%, 51%, and 23%, respectively, at 512 μg/mL. In postharvest assays on broccoli florets, qualitative effects on fungal development were observed.