<p>This study evaluated the ecotoxicity and biosafety of polymeric food packaging composite film that fabricated with chitosan, starch, and taro mucilage, loaded with ZnO nanoparticles (ZnO NPs). The ecotoxicity of the nanocomposite (S-Cs-M-ZnO) was assessed based on seed germination index, phytochemical analysis, plant growth promotion efficacy, and the microflora associated with rhizosphere. The nanocomposite-treated group showed no negative effects on the seedling’s emergence, plant growth promotion efficacy of <i>Vigna radiata</i> with notable changes in the phytochemical constituents. Nanocomposite treatment also exhibited positive impact on the colonization of rhizosphere microflora. In silico analysis showed that the ZnO NPs incorporated into the packaging film did not exhibit plant growth-promoting hormone activity, such as cytokinin or gibberellic acid. These findings confirm that the fabricated nanocomposite film is biocompatible and environmentally safe, making it a promising material for food packaging applications with minimal ecological impact.</p> Graphical Abstract