Synergistic effect of UV-C LED irradiation and PLA/PBAT-based antimicrobial packaging film on fresh-cut vegetables

Abstract

The combined use of ultraviolet-C light-emitting diodes (UV–C LED) irradiation and antimicrobial packaging film was used to secure the safety of fresh-cut vegetables. The antimicrobial packaging film was prepared by adding grapefruit seed extract (GSE) and zinc oxide nanoparticles (ZnO) to a blend film of poly(lactide) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). The GSE and ZnO added film (PLA/PBAT/GSE/ZnO film) showed moderate antioxidant activity of about 36.3% and 21.9% in the ABTS and DPPH methods, respectively, and exhibited strong antibacterial activity against Enterohemorrhagic Escherichia coli (EHEC) and Staphylococcus aureus. The UV-C LED treatment reduced EHEC by 0.47, 0.55, and 0.61 Log CFU/g and S. aureus by 0.46, 0.39, and 0.33 Log CFU/g of fresh-cut onion, cabbage, and carrot, respectively. The combined UV-C LED irradiation and antimicrobial packaging showed a significant synergistic effect in reducing the bacteria during storage. After 7 days of storage at 10 °C, it showed 2.02, 2.82, and 2.06 log CFU/g lower E. coli, and 1.59, 1.77, and 1.47 log CFU/g lower S. aureus in onion, cabbage, and carrot, respectively, than the control group. The combined use of UV-C LED and antimicrobial packaging has a high potential to extend the shelf life of fresh-cut vegetables without heat treatment or the addition of chemical preservatives.