This review article explores the antibacterial activity and toxicity mechanisms of zinc oxide nanoparticles (ZnO-NPs). ZnO-NPs have gained significant attention due to their enhanced antibacterial properties at the nanoscale, attributed to their increased specific surface area and reactivity. The review covers various aspects of ZnO-NPs, including testing methods, the impact of UV illumination, particle properties (size, concentration, morphology, and defects), surface modifications, and minimum inhibitory concentration (MIC). The antibacterial mechanisms are primarily focused on the generation of reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂), hydroxyl radicals (OH⁻), and superoxide ions (O₂⁻²), which lead to cell wall damage, enhanced membrane permeability, and mitochondrial dysfunction. The article also discusses the role of surface defects and Zn²⁺ release in the antibacterial activity. Additionally, it highlights the potential applications of ZnO-NPs in food packaging to combat foodborne diseases. The review concludes by discussing the synthesis methods, crystal structures, and the influence of various physicochemical and structural factors on the antibacterial activity of ZnO-NPs.This review article explores the antibacterial activity and toxicity mechanisms of zinc oxide nanoparticles (ZnO-NPs). ZnO-NPs have gained significant attention due to their enhanced antibacterial properties at the nanoscale, attributed to their increased specific surface area and reactivity. The review covers various aspects of ZnO-NPs, including testing methods, the impact of UV illumination, particle properties (size, concentration, morphology, and defects), surface modifications, and minimum inhibitory concentration (MIC). The antibacterial mechanisms are primarily focused on the generation of reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂), hydroxyl radicals (OH⁻), and superoxide ions (O₂⁻²), which lead to cell wall damage, enhanced membrane permeability, and mitochondrial dysfunction. The article also discusses the role of surface defects and Zn²⁺ release in the antibacterial activity. Additionally, it highlights the potential applications of ZnO-NPs in food packaging to combat foodborne diseases. The review concludes by discussing the synthesis methods, crystal structures, and the influence of various physicochemical and structural factors on the antibacterial activity of ZnO-NPs.