Metallic-based micro and nanocomposites in food contact materials and active food packaging

Metallic-based micro and nano-structured materials are incorporated into food contact polymers to enhance mechanical and barrier properties, and to prevent the photodegradation of plastics. Additionally heavy metals are effective antimicrobials in the form of salts, oxides, and colloids, complexes such as silver zeolites, or as elemental nanoparticles. They are incorporated for food preservation purposes and to decontaminate surfaces in industrial environments. Other relevant properties in active food packaging, such as the capability for ethylene oxidation or oxygen scavenging, can be used to extend food shelf-life. Silver based nano-engineered materials are currently the most commonly used in commodities due to their antimicrobial capacity. Copper, zinc and titanium nanostructures are also showing promise in food safety and technology. The antimicrobial properties of zinc oxide at the nanoscale will provide affordable and safe innovative strategies. Copper has been shown to be an efficient sensor for humidity, and titanium oxide has resistance to abrasion and UV-blocking performance. The migration of cations from the polymer matrices is the key point to determine their antimicrobial effectiveness; however, this cation migration may affect legal status of the polymer as a food-contact material.