Preparation of hybrid particles of Ag nanoparticles and eggshell calcium carbonate and their antimicrobial efficiency against beef-extracted bacteria.

In this study, hybrid particles of AgNPs-loaded eggshell calcium carbonate (AgNPs/eCaCO 3 ) were prepared by co-precipitating the eggshell in the presence of freshly prepared AgNPs with a particle size of 10-30 nm. The hybrid particles were comparatively precipitated at 25°C and 35°C using poly (sodium 4-styrenesulfonate) as a polyelectrolyte. The AgNPs/eCaCO 3 particles prepared at 25°C had a spherical morphology with a mean diameter of 3.56 µm, and Brunauer-Emmett-Teller (BET) surface area of 85.08 m 2 g -1 . On the other hand, the particles prepared at 35°C had a broader size distribution with a mean diameter of 3.19 µm, and a BET surface area of 79.25 m 2 g -1 . AgNPs-loaded commercial calcium carbonate particles (AgNPs/CaCO 3 ) comparatively prepared at 35°C were perfectly spherical with a mean diameter of 5.61 µm. At preparing temperature of 25°C, the hybrid particles contain AgNPs of 0.78 wt% for AgNPs/eCaCO 3 and 3.20 wt% for AgNPs/CaCO 3 . The AgNPs/eCaCO 3 and AgNPs/CaCO 3 particles exhibited the same efficiency against bacteria extracted from beef with an average inhibition zone diameter of 7-10 mm according to the modified Kirby-Bauer disc diffusion assay depending on their concentration and beef source. Freshly prepared silver colloids showed comparatively poorer antimicrobial efficiency.