Development of PLA-PVA/LZ cellulose pads with antimicrobial activity and their application in instant cooked rice preservation

This study developed an antibacterial pad by immobilizing lysozyme (LZ) within porous cellulose through polyvinyl alcohol (PVA) cross-linking, reinforced with polylactic acid (PLA) barrier layers. The PLA-PVA/LZ pad demonstrated significantly enhanced structural properties, including a 65.52% increase in TS, a 78.88% rise in WCA, and an 87.62% reduction in water absorption. At an optimal loading of 4% LZ, the pads exhibited potent antibacterial efficacy, inhibiting <i>Staphylococcus aureus</i> (<i>S. aureus</i>) and <i>Escherichia coli</i> (<i>E. coli</i>) growth by 93.93% and 86.73%, respectively. Mechanistic investigations revealed that the pad disrupted bacterial cell morphology, compromised membrane integrity, suppressed ATPase activity, and elevated AKP levels. When applied to cooked rice stored at 25 °C, the pad effectively maintained microbial counts below the detection limit for 48 h, extending shelf life by at least 12 h according to Chinese national standards.