Pseudomonas aeruginosa-derived carbon dots doped with sulfur as active packaging materials for fresh food preservation

Bacteria (Pseudomonas aeruginosa)-derived carbon dots (PCDs) were successfully synthesized via a hydrothermal method and further doped with sulfur to improve their functional properties, such as antioxidant and antimicrobial activities. Sulfur-doped PCDs (S-PCDs) exhibited excellent antioxidant activities of 94.98% for ABTS and 83.63% for DPPH radical scavenging rate and strong antimicrobial activity of 21.63 mm inhibition zone against Listeria monocytogenes with a slight reduction in the photoluminescence intensity. S-PCDs were incorporated into polyvinyl alcohol (PVA)-based films with different concentrations (0.5, 1, and 2%) and significantly increased the UV-blocking property from 22.55 to 97.17% without affecting the film transparency. When the PVA/S-PCDs composite films were used to package pork meat and sliced apples, the shelf life of these foods can be extended by reducing microbial contamination of pork meat and inhibiting the browning of sliced apples. Therefore, PVA/S-PCDs composite films showed great potential as an active packaging for various foods.