Enhancing safety and synergy: a supported Ag@NiZnAl-LDH antimicrobial polyethylene film for dairy product packaging

Dairy products are highly susceptible to contamination by microorganisms such as bacteria, mold, and yeast. This contamination not only deteriorates their quality but also poses significant health risks to consumers. To address this issue, we developed a novel composite film by loading silver (Ag) onto the surface of NiZnAl layered double hydroxide (LDH) nanosheets using a hydrothermal method, and subsequently combining this with low-density polyethylene (LDPE). The results showed that the inhibition rate of Ag@NiZnAl-LDH against Staphylococcus aureus, Escherichia coli and Aspergillus brasiliensis was 99.8%, 99.9% and 100.0%, respectively, due to the synergistic effect of the LDH and the loading of Ag. A significant difference in zeta potential and the enhanced hydrophilicity of Ag@NiZnAl-LDH led to strong attractive forces between the nanocomposites and the microorganism surfaces. Subsequently, Ag@NiZnAl-LDH could kill by disrupting the microbial cell membrane. Loading 5 wt% Ag@NiZnAl-LDH in a PE composite film led to inhibition against Staphylococcus aureus, Escherichia coli and Aspergillus brasiliensis of 81.7%, 95.3% and 93.4%. Moreover, simulation of the ion migration process in dairy products was performed, and the film was shown to have acceptable safety. The LDH/PE composite film not only retains the high antimicrobial ability of the metal ions, but also improves the safety of the formulation. As a potential dairy product packaging material, it has potential value for application in the food field.