Synthesis and Characterization of Nanomaterial-Coated Chitosan-Based, Biodegradable Film for Antimicrobial Food Packaging

Microbial contamination and plastic packaging pose significant health and environmental risks and are nonrecyclable. Biomaterials are gaining popularity in food packaging due to their biodegradability, renewability, and eco-friendly nature. Therefore, zinc oxide-chitosan-based nanocomposite (ZnOCh) films were synthesised in this study as a biodegradable food packaging material. Three composite films were prepared, containing different concentrations of nanoparticles (1%, 2%, and 3% wt) and pure chitosan. Ultraviolet-visible and Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, energy-dispersive X-ray, and scanning electron microscopy were used for characterisation. The films were also characterised for their biodegradability and ability to enhance the shelf life of chicken meat. Two bacterial strains were isolated from chicken meat and identified: SHA as Klebsiella pneumoniae (PQ313102) and SHC as Serratia marcescens (PQ312920). The appearance of a peak at 370 nm in UV-visible spectra confirms the formation of zinc oxide nanoparticles. The SEM revealed a smooth surface of ZnOCh film with scattered nanoparticles, while degraded film showed less scattering and a rougher surface. The formation of peaks at 432 and 471 cm^-1 in FTIR spectra confirmed the incorporation of ZnO, attributed to Zn–O stretching vibrations. ZnOCh 1% showed statistically significant degradation (96.50% ± 0.56%) after 14 days, and these films also showed promising results in increasing the shelf life of meat after 12 days of storage at 4°C. ZnOCh films showed significantly high (p ≤ 0.000) antibacterial activity (upto 19.6 ± 0.4 mm inhibition zone) against both erythromycin-resistant bacterial strains. Based on these results, this study suggests that ZnOCh films could be an alternative to plastic food packaging materials.