Mechanism of antimicrobials immobilized on packaging film inhabiting foodborne pathogens. (1st November 2022)

• Record Type: Journal Article
• Authors: Hao, Yi; Zhang, Mengmeng; Wang, Li; Tao, Ningping; Li, Li; Zhu, Weizhong; Xu, Changhua; Deng, Shanggui; Wang, Yifen
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 169(2022)
• Publication Date: 2022-11-01
• Subjects: Immobilized -- Antibacterial mechanism -- Cell membrane -- DNA; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2022.114037
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: Non-migrating active packaging can provide long-lasting and safe antibacterial effects; however, the underlying antibacterial mechanism remains unclear. In this study, chitosan (CS) and lysozyme (LYS) were covalently immobilized on a polylactic acid (PLA) film to produce functional packaging films, chitosan-graft-polylactic acid (CS-g-PLA) and lysozyme-graft-polylactic acid (LYS-g-PLA). The antimicrobial effects and mechanisms of action of these films against Staphylococcus aureus and Escherichia coli were investigated. The minimum inhibitory concentrations (MICs) of the CS and LYS against S. aureus were both 1.25 mg/mL; the MIC against E. coli was 1.25 mg/mL for CS and 2.5 mg/mL for LYS. Scanning and transmission electron microscopy revealed physical damage, significant morphological changes, and intracellular component leakage from bacterial cells after treatment with antimicrobial agents. Cell integrity and conductivity tests showed that bacterial cell membrane integrity was destroyed, and its permeability changed. The gel retardation assay showed that the CS-g-PLA film affected the bacteria by binding to genomic DNA. The results showed that the grafted films effectively inhibited S. aureus and E. coli . CS-g-PLA and LYS-g-PLA films inhibited bacterial growth by destroying the integrity of bacterial cell membranes and promoting changes in membrane wall permeability. In addition, immobilized CS can enter bacterial cells and bind with DNA, thus inhibiting the growth and reproduction of bacteria. Graphical abstract: Possible mechanisms of bacteriostasis by free or immobilized antimicrobial agent against E. coli and S. aureus. Image 1 Highlights: Chitosan (CS) and lysozyme (LYS) were immobilized on polylactic acid (PLA) films. Their effect and mechanism of action against S. aureus and E. coli were evaluated. Weakened bacterial cell membrane integrity led to intracellular component leakage. The CS-g-PLA film affected bacterial growth by binding to genomic DNA.