A novel preservation technique applied to fiordilatte cheese

Bio-plastics are starting to graduate from the 'emerging technology' stage to market acceptance as everyday materials. In the present study, nanocomposite coatings embedding copper nanoparticles (CuNPs) were developed as new active packaging for fresh dairy products. In order to combine the bioactivity of CuNPs with a biodegradable polymer matrix, copper nanoparticles were satisfactorily incorporated into polylactic acid (PLA). Two different routes were carried out to prepare active films by picosecond-pulsed laser ablation. The nano-materials were characterized by UV-Vis spectroscopy and X-ray Photoelectron spectroscopy. Copper release was also measured through atomic absorption analyses. To assess the antimicrobial effects of nanocomposite systems, both in vitro and in vivo tests were carried out. The active polylactic acid films showed good antibacterial activity. In fiordilatte samples stored at 4 degrees C during 9 days, proliferation of main spoilage microorganisms was delayed with a consequent preservation of sensory attributes. These results represent a step forward in the possible application of copper in the food packaging industry. Industrial relevance: Bio-plastics with active properties represent the most emerging technology in food packaging field. Results from the current paper demonstrate that antimicrobial films of PLA embedding copper nanoparticles could be developed and applied to fresh dairy products as fiordilatte. In fact, the in vivo test confirmed the antimicrobial effects on fiordilatte spoilage, without compromising sensory attributes. Results could gain great importance from the industrial dairy sector. (C) 2013 Elsevier Ltd. All rights reserved.