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Abstract
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This study was aimed to fabricate a durable antimicrobial packaging film using electrospun polylactic acid (PLA) nanofibers containing Thymus daenensis essential oil (TDO), TDO-loaded mesoporous silica vesicles (MSVs/TDO), and MSVs/TDO combined with silver nanoparticles (AgNPs). Functional features including mechanical properties, heat resistance, water vapor permeability (WVP), antimicrobial and release behavior of TDO and AgNPs from the nanofibers were assessed. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed the presence of MSVs/TDO and embedded AgNPs in nanofibers. Application of MSV/TDO along with AgNPs could reduce significantly the WVP (0.43 ± 0.04 g m−1 Pa−1 s−1) and control the release of the EO from the electrospun PLA films (P < 0.05). Furthermore, the release of AgNPs from PLA nanofibers was increased in the presence of pure TDO (0.0135 ppm after 72 h). The combination of MSVs/TDO and AgNPs had a synergistic antibacterial effect on the tested bacteria both in culture and on ultra-filtered (UF) cheese. The controlled release ability of the EO in MSVs/TDO film resulted in its less antibacterial effect compared to the TDO film in the early times of antimicrobial assessments. The population growth of the inoculated pathogenic bacteria on the packed UF cheese with the films containing MSVs/TDO was controlled due to the long-lasting release of EO, so that the MSVs/TDO + AgNPs film reduced the count of E. coli and S. aureus by 1.56 and 2.97 log CFU g−1 on the 4th storage day, respectively. Thus, the electrospun PLA film containing MSVs/TDO + AgNPs bear a good potential for use in food packaging as a biocompatible packaging with long-term antimicrobial performance.
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