Pathway-oriented functional films for animal-derived foods: Spoilage mechanisms, targeted packaging strategies, and industrial translation

Background Functional films are widely studied for preserving red meat, poultry, and aquatic products. However, most reviews classify these films by material, active compound, or fabrication method. Such classifications provide limited guidance for selecting film functions for specific food systems. A pathway-oriented framework is therefore needed. Scope and approach This review organizes functional films according to the processes that limit marketable shelf life. It compares oxidative deterioration, microbial spoilage, and autolysis-related structural decline in red meat, poultry, and aquatic products. It also examines how package-atmosphere dynamics regulate these processes. Major film functions are then matched with specific deterioration processes and packaging conditions. These functions include oxygen control, antioxidant protection, interfacial antimicrobial action, moisture and exudate management, gas regulation, scavenging, and freshness monitoring. Real-food validation, safety, sensory compatibility, manufacturability, regulation, and industrial translation are also discussed. Key findings and conclusions Preservation priorities differ among food systems and packaging scenarios. Red meat requires a balance between colour retention and oxidative stability. Poultry is mainly affected by surface microbial growth, exudate accumulation, and odour deterioration. Aquatic products are affected by lipid oxidation, autolytic softening, amine-producing spoilage, drip loss, and gas-environment changes. Multifunctional films should therefore target the main shelf-life-limiting process first. Supporting functions should address coupled deterioration processes. Film performance should be validated in real foods under realistic packaging and cold-chain conditions. Evaluation should combine gas composition, colour, oxidation, microbial counts, volatile nitrogen compounds, drip loss, texture, and sensory rejection. This framework can support evidence-based film selection and industrial translation.