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

<i>Staphylococcus aureus</i>, 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 <i>S. aureus</i>. 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.