In all packages except pure LDPE, and LDPE + 1% nano-ZnO, significant decrease (p < 0.05) of L. plantarum populations, were achieved ( Fig. 4).
By increasing nano-ZnO concentration to 1%, the antimicrobial activity of the film decreased. This was due to the agglomeration of nanoparticles during the processing of the film.
In contrast, by increasing the nanosilver concentration, the antimicrobial activity of the film increased. The reduced antimicrobial activity of ZnO powder might be related to the increasing particle size, which might decrease the generation of H2O2 from the surface of ZnO powder.
However, nanpcomposite packaging exhibited a pronounced effect on the destruction of microorganisms in orange juice and LDPE + 5% P105 packages showed a higher antimicrobial activity compared with others (Fig. 4).