Synthesis of Ag and Ag–SiO2 nanoparticles by γ-irradiation and their antibacterial and antifungal efficiency against Salmonella enterica serovar Typhimurium and Botrytis cinerea

The Ag and Ag–SiO2 nanoparticles were synthesized by γ-irradiation, and characterized by field-emission transmittance electron microscopy (FE-TEM), field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDXS). The electron microscopy images show that well-dispersed Ag nanoparticles of about 7 nm were attached to the surface of SiO2 nanoparticles of about 350 nm. Antibacterial efficiency of the Ag–SiO2 nanoparticles was tested against Salmonella enterica serovar Typhimurium by measuring the optical density (OD). Without Ag–SiO2 particles, the S. enterica serovar Typhimurium grow gradually, and reach a steady state (fully grow) in about 6 h. At the presence of Ag–SiO2 particles at 50 ppm, their growth became much slower, reaching a steady state after about 24 h. With Ag–SiO2 particles at 100 ppm, they did not grow fully even after 58 h. The antifungal efficiency of the Ag–SiO2 nanoparticles against Botrytis cinerea was about 65.0, 99.9, and 99.9% at the concentrations of the particles of 10, 50, and 100 ppm, respectively.