Development of a sodium alginate-silver/zinc oxide – cinnamaldehyde nanocomposite film for coating chicken meat and evaluation of meat safety

Abstract

Developing sustainable and edible active packaging materials is critical to mitigate microbial contamination and enhance food safety. This study developed a biodegradable and edible active film incorporating green-synthesized silver-zinc oxide nanocomposites (Ag/ZnO NCs) entrapping cinnamaldehyde (Ag/ZnO–N) in a food-grade alginate matrix for preservation of chilled chicken meat. The Ag/ZnO–N exhibited antibacterial activity against multi-drug-resistant (MDR) enteroaggregative Escherichia coli, Salmonella spp., and methicillin-resistant Staphylococcus aureus, with a minimum inhibitory concentration and minimum bactericidal concentration (MBC) of 7.80 and 62.50 µg mL⁻¹, respectively. UV-vis and Fourier-transform infra-red spectroscopic analyses confirmed nanoparticle formation and cinnamaldehyde entrapment, while X-ray diffraction and scanning electron microscopy revealed polycrystalline morphology with reduced lattice crystallinity. The NCs exhibited minimal cytotoxicity to Vero cells (83.35% viability at 10⁻⁵ mg mL⁻¹). Alginate (5%) films incorporating Ag/ZnO–N at MBC levels demonstrated enhanced surface roughness by atomic force microscopy, functional group integration, and potent antioxidant capacity (74.50 ± 0.14% ABTS^˙+ and 8.38 ± 1.18% DPPH radical scavenging). The films were non-inhibitory to commensal microflora and exhibited significant antibacterial efficacy against MDR pathogens. In an ex vivo study on vacuum-packed chicken meat stored for 15 days under chilling conditions, the film significantly (P < 0.05) reduced aerobic plate, psychrotrophic, E. coli, and S. aureus counts, while Salmonella spp. were undetected. Lipid oxidation remained negligible and inductively coupled plasma mass spectrometry confirmed the absence of Ag⁺ and Zn²⁺ migration. These findings demonstrate that alginate-Ag/ZnO–N film offers a safe, edible, functional, and environmentally sustainable biomaterial platform for meat preservation, supporting circular bioeconomy-driven food systems.