Application of LDPE Nanocomposite Films Incorporating Organoclay Modified with Nanometals in Packaging of Lighvan Cheese

Lighvan cheese is one of the most popular traditional Iranian cheese due to its excellent taste and flavor. It is traditionally made from unpasteurized (raw) milk, thus, the presence of pathogen and spoilage microorganisms in the fresh final product is inevitable. The aim of this study was to evaluate the use of active LDPE based nanocomposite films containing different metallic and clay nanoparticles in packaging of Lighvan cheese. Cheese packages were prepared from nanocomposite films and stored at 4 oC. Physical and chemical analyses and microbial tests of the packed cheeses were done immediately after packaging (at day 0), and after 7, 14, 21 and 28 days of storage. After 28 days of storage, the growth rate of coliformbacteria and Staphylococcus aureus was significantly (p<0.05) decreased as a result of application of nanocomposite package containing nanometals; however, it did not affect the growth of lactic acid bacteria. The results of migration test of nano-metal particles from package into a food simulant showed that nanocomposites containing metal nanoparticle was safe according to the limits set by FDA and EFSA. Packaging containing nanoclay modified with nano-Ag and nano-CuO would reduce coliform bacteria and Staphylococcus aureus with no detrimental effect on cheese micribiota.