A dual-function chitosan packaging film for simultaneously monitoring and maintaining pork freshness

Exploring food packaging films simultaneously possess freshness monitoring and maintaining can effectively tackle food safety issues. Here, we constructed a chitosan/N-doped carbon dots (CS/N-CDs) film which can monitor the freshness of pork based on pH-mediated fluorescent sensing and extend the shelf life based on the antioxidant, antibacterial and UV shielding properties. The fluorescent intensity of CS/N-CDs films increased with the increase of pork pH from 5.77 to 6.84 which positively related to the change of TVB-N from 6.68 to 17.53 mg/100 g. CS/N-CDs films had a maintaining effect on pork freshness corroborated by the scavenging activity on DPPH and ABTS radicals and antibacterial efficiency and inhibition zones of S. aureus and E.coli , and the total viable count, a value, weight loss, hardness and springiness of pork. Cell viability and hemolytic activity assay proved that CS/N-CDs films was safe. A novel chitosan-based intelligent and active food packaging film was provided.