FUNCTIONALIZED SILICA GEL WITH Ag AND ZnO NANOPARTICLES ON ANTIMICROBIAL PROPERTIES AND THEIR APPLICATION IN ABSORBENT PADS

This study investigates the functionalization of silica gel, derived from renewable sources of rice husks, functionalized with silver (Ag) and zinc oxide (ZnO) nanoparticles for use in antimicrobial absorbent pads intended for active meat packaging applications. Silica matrices were synthesized and subsequently decorated with Ag through chemical reduction and ZnO through precipitation methods. A comprehensive characterization was performed to evaluate metal loading efficiency, leaching behavior in aqueous media, and antimicrobial activity against Pseudomonas aeruginosa, a Gram-negative bacterium associated with spoilage. Agar diffusion and minimum inhibitory concentration (MIC) tests revealed that Ag-functionalized silica exhibited significant antimicrobial efficacy, with MIC values ranging from 15 to 21 µg mL–1. In contrast, ZnO-functionalized silica demonstrated negligible inhibition, attributed to the known zinc homeostasis mechanisms of P. aeruginosa. The application of functionalized silica in absorbent pads significantly reduced bacterial counts during refrigerated storage of beef samples for 96 h, particularly with Ag-SiO2. These findings highlight the potential of Ag-based nanostructures supported on silica gel as effective antimicrobial components for sustainable active food packaging.