The Effectiveness of Nanocomposite Films Against Gram-Positive and Gram-Negative Foodborne Pathogenic Bacteria

In this research, nanocomposites consisting of a mixture of linear low-density polyethylene polymer (LLDPE) and zinc oxide nanoparticles (ZnO-NPs) were prepared. The films of the composite material were formed with five weight ratios (0.25, 0.5, 1, 2.5, and 5wt%) in addition to pure LLDPE, intended to investigate the role of nanomaterials in improving the performance of some properties of LLDPE polymer such as increasing the shelf life of food products and protecting the consumer from pathogenic germs in food packaging applications. The efficacy was evaluated against pathogenic bacteria, Escherichia coli and Staphylococcus aureus, through the standard "ISO 22196". The test results confirm that the nanocomposite films containing 0.5wt% or more of nano-zinc oxide have bacteriostatic activity. This activity increases with the increase of ZnO-NPs in the LLDPE polymeric phase, and the highest antibacterial effect was in the nanocomposite films of 5wt%. It was found that gram-positive bacteria were more sensitive to ZnO-NPs than gram-negative bacteria and that these nanocomposite films can provide a safe way to preserve food without the need for food processing.