Development of moisture-responsive H₂O₂-releasing composite films for antimicrobial food packaging applications

This study introduces H₂O₂-releasing films by incorporating CaO₂ into poly(lactic acid)/polyethylene glycol (PLA/PEG) composites by melt extrusion and establishes a practical composition window that correlates PEG concentration with H₂O₂-release performance and shelf-life extension. To our knowledge, melt-extruded CaO₂-containing films have been rarely investigated for antimicrobial packaging applications. PEG acts as a plasticizer and hydrophilic agent, enhancing film flexibility and moisture uptake, thereby facilitating CaO₂ hydrolysis and H₂O₂ release. Composite films containing ≥ 20 wt% PEG released 67 ppm of H₂O₂ within 12 h and achieved 99.999% bacterial reduction against Escherichia coli and Staphylococcus aureus. Storage tests with cherry tomatoes demonstrated that PLA/PEG/CaO₂ films delayed fruit deterioration and extended shelf life to 13 d. Migration test confirmed that films with ≤ 20 wt% PEG comply with the European Union regulatory limit. Within this compliant range, the developed PLA/PEG/CaO₂ composite films are safe and effective antimicrobial packaging materials, especially for fresh produce.