Antimicrobial properties of polypropylene films containing AgSiO₂, AgZn and AgZ for returnable packaging in seafood distribution

Active antimicrobial films were prepared by incorporating AgSiO₂, AgZn and AgZ at 1, 3, 5 and 10 % (w/w) into a polypropylene (PP) matrix. Complete thermal, structural, mechanical and functional characterization as well as antimicrobial efficiency and returnable antimicrobial efficiency were determined according to the Japanese Industrial Standard method. The morphology of the films showed agglomerates of particles in the composites. The active formulation had decreased elongation compared to the pure PP sample. Thermal analyses indicated that the active formulation compositions had increased thermal stability. The films showed 50 % antimicrobial properties after the fifth wash against the tested microorganisms, presenting better activity against Gram negative organisms than Gram positive ones. These findings suggest that PP films with AgSiO₂, AgZn and AgZ particles can provide a significant contribution to the quality and safety of seafood in the distribution chain.