Fabrication of anti-Listeria film based on bacterial cellulose and Lactobacillus sakei-derived bioactive metabolites; application in meat packaging

Abstract

More recently, probiotics-derived bioactive metabolites (so-called postbiotics; P) have gained more attention for antimicrobial food packaging. In this study, anti-Listeria active packaging films containing bacterial nanocellulose (BNC) and postbiotics of Lactobacillus sakei were fabricated, and their antibacterial performance was examined in in vitro condition and patty of buffalo meat. To facilitate postbiotics incorporation, ultrasound-assisted coating (UC, 40-kHz) and common coating (CC) were applied. The concentration of postbiotics and coating time were optimized by response surface methodology (RSM) and central composite design, and the antimicrobial activity of films was assessed by the disk diffusion method. The FTIR, mechanical, and surface morphologies of BNC-CC-P and BNC-UC-P films in optimized conditions (17 and 30% of postbiotics and 10 min coating time) were investigated. Based on the FTIR and SEM data, UC facilitated postbiotics incorporation into BNC, while tensile strength and elongation at break of BNC-CC-P and BNC-UC-P films were decreased and increased, respectively. Even though Listeria counts in patties with BNC film followed a similar trend with control samples without film and passed 107 CFU/g, samples wrapped with BNC-CC-P and BNC-UC-P films represented a 2.3 and 2.6 log CFU/g reduction in the bacterial count during storage (9 days at 8 °C), respectively. The findings of this work have provided worthwhile insights into the use of postbiotics in antimicrobial meat packaging for the control of foodborne pathogens. Ultrasound-assisted coating facilitated the rapid release of postbiotics from BNC into the meat matrix, signifying the importance of such a film for the packaging of foods having a short shelf life.