Advanced antimicrobial surfaces in cellulose-based food packaging

This critical review provides a comprehensive framework for selecting engineered colloidal and nanostructured systems for cellulose-based food packaging. Meta-analysis was used as a methodological approach to categorize them according to antimicrobial agents, coating methods, and synergistic effects against a broad spectrum of microorganisms. The most frequent substrate is flexible packaging paper (35-70 g/m², uncalendered), often intended for food wrapping. Among antimicrobial agents, chitosan-based coatings are a common choice-often combined with essential oils-being particularly effective against Gram-positive bacteria (e.g., Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis). This is attributed to electrostatic interactions between the polysaccharide's protonated -NH₃⁺ groups and teichoic acids within bacterial cell walls. Inorganic metal nanoparticles, such as ZnO nanorods and Ag nanoparticles, are broadly effective by compromising the membranes of various foodborne pathogens-including Bacillus cereus and Pseudomonas aeruginosa. Terpenoid- or phenolic-rich essential oils-commonly delivered in emulsions or encapsulated in host-guest β-cyclodextrin complexes-inhibit the growth of yeasts and molds, besides some common bacteria when grafted onto bleached paper. Synergistic effects have been observed with complex coatings such as chitosan combined with CuONPs. Despite their promising performance, the widespread industrial adoption of cellulose-based active packaging in the food sector requires addressing not only antimicrobial activity, but also barrier properties and feasible methods to functionalize the paper surface (e.g., bar coating). These challenges, often overlooked, are critically assessed herein. All considered, further studies are required to address the challenges of cellulosic antimicrobial materials in a holistic manner to accelerate its large-scale implementation in the food sector.