Biodegradable Films Targeting Staphylococcus aureus: Structure–Function Synergies and Interfacial Mechanisms

Staphylococcus aureus, particularly its multidrug-resistant strains, poses a critical biological hazard throughout the global food supply chain, underscoring the need to transition from inert petroleum-based packaging to active, biodegradable alternatives. This review presents a comprehensive analysis of the structure function relationships and interfacial interaction mechanisms that govern polysaccharide-, protein-, and lipid-based films designed for the targeted inhibition of S. aureus. We critically evaluate the extent to which the intrinsic molecular features—such as the polycationic charge density of chitosan and the amphiphilic self-assembly of fatty acids—determine baseline antibacterial activity. A key contribution of this work is the elucidation of three synergistic pathways: physical barrier effects, chemical interference, and biological regulation. Furthermore, we discuss how composite systems, such as polysaccharide lipid hybrids and protein nanomaterial scaffolds, exploit charge complementarity and controlled-release kinetics to surpass the performance limitations of single-component materials. Finally, we address the critical trade-offs between mechanical integrity and antimicrobial efficacy, proposing a roadmap for intelligent, stimuli-responsive packaging that is capable of responding to microbial metabolic cues. Overall, this review provides a theoretical foundation for the rational design of high-performance biodegradable films to safeguard global food safety.