GREEN SYNTHESIS OF SILVER NANOPARTICLES AND THEIR ANTIBACTERIAL ACTIVITY AGAINST FOODBORNE PATHOGENS

Abstract

This study aimed to green-synthesize silver nanoparticles (AgNPs) using leaf extracts from Holy basil, Sweet basil, and Tree basil as bioreducing agents, thereby replacing conventional chemical methods. The synthesis successfully yielded spherical AgNPs with a nanometer scale size, exhibiting a maximum surface plasmon resonance (SPR) absorption peak in the 400–480 nm range. The resulting fine, dark-brown powder was then evaluated for its antibacterial efficacy against the foodborne and spoilage bacteria, E. coli, S. aureus, and Alcaligenes sp., using the agar well diffusion method. The results confirmed that all synthesized AgNPs effectively inhibited the growth of all three bacterial strains. Specifically, AgNPs derived from Sweet basil extract demonstrated the highest overall inhibitory effect, followed by those from Holy basil and Tree basil extracts, respectively. Furthermore, across all plant extracts, the prepared AgNPs consistently exhibited the highest antibacterial activity against S. aureus, followed by E. coli and Alcaligenes sp., in descending order.