Cold atmospheric plasma for producing antibacterial bilayer films of LLDPE/cassava starch added with ZnO-nanoparticles

Active antimicrobial materials for food packaging increase food shelf stability and reduce food additives. This study investigated the cold atmospheric plasma (CAP) for obtaining antimicrobial bilayer films formed by linear low-density polyethylene (LLDPE) and cassava starch suspension incorporated with zinc oxide nanoparticles (ZnO-NPs). The adherence between LLDPE and starch was promoted by treating LLDPE with CAP from a dielectric barrier discharge reactor (DBD) operated at 32 kV and 132 Hz for 120 s, which increased LLDPE surface free energy and hydrophilicity. The antibacterial activity of the bilayer films was tested against pathogenic and spoilage bacteria, Staphyloccocus aureus, Salmonella Enteritidis, and Lactobacillus sakei. The films inhibited the three bacteria effectively, although L. sakei was less sensitive to the ZnO-NPs. The bilayer packaging material presented mechanical properties similar to those of the single LLDPE. Therefore, LLDPE-Starch-ZnO-NPs films have a high potential for use as active food packaging to increase food safety and shelf life.