Food grade zinc oxide bulk particle composite can replace the toxic zinc oxide nano composite towards the control of pathogenic and spoilage bacteria.

ZnO-Nanoparticle-Chitosan (ZnO-NP-CH) composite has potential biomedical and food applications due to its better antimicrobial activity. However, the presence of nano-metal-oxide in the composite makes the material unsuitable for any food applications. Moreover, the cost involved in the preparation of Zinc Oxide-Nano-Particle (ZnO-NP) is a major limitation for commercial food applications. Hence a suitable alternative for ZnO-NP is highly needed for food application. Since ZnO-Bulk Particles (ZnO-BP) are food grade and there is no study on the composite prepared from ZnO-Bulk Particle-Chitosan (ZnO-BP-CH), in the present study, antimicrobial activity was assessed for ZnO-BP-CH and compared with ZnO-NP-CH. Based on the study, it was observed that in the individual form of ZnO-NP possessed significantly higher antimicrobial activity than ZnO-BP. The composite form of ZnO-NP-CH and ZnO-BP-CH possessed higher antimicrobial activity than chitosan. However, no significant difference was observed between the composite forms. Hence, ZnO-BP-CH could be recommended as a suitable alternative to ZnO-NP-CH for future studies related to chitosan with ZnO composite to avoid costly nanomaterials preparation.