Antimicrobial resistance is a growing global public health threat, with the rapid rise of multidrug-resistant microbes becoming alarming. The quest for natural antimicrobials has increased as consumers seek safer alternatives for ensuring food safety, nutrition, and sensory quality. This current study investigates the antimicrobial activities of biosynthesized silver nanoparticles (AgNPs) from metabolites of lactic acid bacteria (LAB) isolated from Cyperus esculentus milk. LAB were isolated and characterized using conventional and molecular methods. Metabolites from the LAB strains were used to synthesize AgNPs. The AgNPs were characterized using UV-Visible Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX). Antimicrobial assay was done using agar well diffusion method. Results from the study showed that Lactobacillus plantarum has the highest occurrence (37.5%) and Lactococcus acidophilus (4.2%) occurred least. UV-Vis confirmed the formation of LAB metabolite-synthesized AgNPs with absorbance peaks at 450 and 500 nm. Transmission Electron Microscopy revealed spherical AgNPs ranging from 1.32 to 23.22 nm, with size variations attributed to different LAB strains. EDX results indicated a significant presence of silver, with weak signals of other elements. The biosynthesized AgNPs possess antibacterial and antifungal activities against selected food pathogens. Lactobacillus plantarum strain 218 had the strongest antibacterial activities (22±2.00 mm) against Staphylococcus aureus. L. plantarum strain a27 had the strongest antifungal activities (11.5±0.71 mm) against Aspergillus flavus. Silver nanoparticles synthesized from the metabolites of LAB isolated from C. esculentus milk therefore show great potential as natural antimicrobials offering an alternative to combat antimicrobial resistance and improve microbial food safety.

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