Purpose: The aim of this study was to improve the flexibility and antimicrobial ability of BC by mixing BC with Polyvinyl Alcohol (PVA) and incorporating nanoparticles into the film.
Methods: BC was synthesized by statically growing Gluconobacter xylinus in Hestrin and Schramm (HS) medium at 26°C for 7 days. Its flexibility was improved by mixing the BC slurry with 3% PVA solution. Nanosilver (AgNPs) was incorporated in the film by immersing the film in AgNO3 solution and NaBH4solution (R film) or simply mixing AgNPs with the film solution (M film). The two films were used in antimicrobial tests against various foodborne pathogens via an agar plate assay and by incubation in tryptic soy broth containing the films and plating at different time points over a 24-h period.
Results: The R film exhibited an obvious inhibition zone against Escherichia coli O157 in the agar assay. In contrast, no inhibition zone was observed for the control and M films. The number of E. coli O157:H7 grown with the R film was 22% lower than the other groups after 3 h incubation, 25% lower after 6 h and 15% lower after 24 h. This indicated that the R film in which the AgNPs were evenly dispersed has higher antimicrobial efficacy against E. coli O157:H7.
Significance: Development of antimicrobial packaging material using BC may provide a more efficient way to control foodborne pathogens.