Abstract

This study investigates the antibacterial properties and stability of green-synthesized silver nanoparticles (AgNPs) using Cymbopogon citratus extract, with a focus on their synergistic effects with conventional antibiotics (Abs) and potential applications in food safety. The AgNPs were evaluated against nine bacterial strains, both alone and in combination with standard Abs (ampicillin (Amp), chloramphenicol (Chl), kanamycin (Km), and penicillin (Pen)) using the agar well diffusion method. Combining AgNPs with Abs significantly enhanced antibacterial activity against several strains, notably Escherichia coli with Km (26.90%), Klebsiella pneumoniae with ampicillin (21.66%), and Staphylococcus aureus with Chl (46.93%). However, certain combinations, such as Pen with Bacillus subtilis and K. pneumoniae, showed reduced effectiveness. Stability studies revealed that AgNPs stored in distilled water (DW) at 4 °C over 40 days exhibited a gradual decrease in absorbance (from 0.221 – 0.142 a.u.) and a slight wavelength shift (423 nm – 420 nm), indicating minor changes in their optical properties. The results highlight the potential of AgNPs as antimicrobial agents capable of enhancing Ab efficacy, with promising applications in food preservation and packaging to combat foodborne pathogens and extend shelf life.

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