Antimicrobial activity of buckwheat starch films containing zinc oxide nanoparticles against Listeria monocytogenes on mushrooms

Buckwheat starch (BS) films containing zinc oxide nanoparticles (ZnO-N; 0%, 1.5%, 3% and 4.5%) were prepared, and their physical, optical and antimicrobial properties were examined. As ZnO-N content increased from 0% to 4.5%, TS increased from 14.99 to 19.09 MPa and Delta E decreased from 25.60% to 20.65%. In addition, L* and a* values decreased, whereas b*, E and opacity increased. Regarding antimicrobial activity, the BS/ZnO-N films had the reductions of 2.96-3.74 log CFU mL(-1) against Listeria monocytogenes after 8 h based on viable cell count assay. The BS film containing 3% ZnO-N, an optimal concentration chosen in this study, was applied to fresh-cut mushroom packaging, and the film exhibited antimicrobial activity against L. monocytogenes, resulting in a reduction of 0.86 log CFU g(-1) after 6 days of storage. Thus, these results indicate that the BS/ZnO-N film can be used as a biodegradable packaging material.