Effects of Nanocoatings Containing Copper on the Microbial and Physical Characteristics of Milk as Compared to Regular Polyethylene Packaging

Introduction: The application of using nanotechnology in food packaging is mixing nanoparticles with packaging material to prevent bacterial deterioration and loss of nutriants in order to improve the shelf life. The aim of this study is to extend the shelf life of milk by the application of the antibacterial polyethylene packaging that consists of copper nanoparticles. Materials and Methods: Nanocomposite film consisted of copper nanoparticles was prepared by using industrial extruder for milk packaging at 4oC. Microbial stability, pH variation, thermal stability and nanoparticle release at zero, 7 to 45 days of storing and water vapour permability for the nanocomposite were analyzed in triplicate order. Results: Microbial analysis indicated that the growth rate in nanocomposite consisted of copper nanoparticles decreased significantly by 38 days of storage. pH variations and acid production due to milk deterioration indicated the quality during storage. Thermal analysis of milk after 38 days of packaging in nanocopper packaging confirmed the level of deterioration during storage. The amount of copper released in milk was within permitted level (2.1ppb). SEM and TEM images indicated the presence of copper nanoparticles in polymer base and its hemogeneous distribution in polymer matrix. The application of nanoparticle in milk caused an increase in shelf life. The results showed that by increasing the concentrations of copper nanoparticles, moisture absorption of the film is decreased. Conclusion: The results indicated that synthesized copper/polyethylen composite increased the shelf life of milk during storage.