Practical application of ZnO-NPs (20nm) suspension with different concentrations (5mM, 8mM, and 10mM) were investigated to evaluate its antibacterial effect in fresh meat. A total number of 12 samples of fresh meat were collected from different abattoirs (150 gm. of each) in Gharbia Governorate, Egypt, under complete aseptic conditions and transferred without undue delay to the Lab to evaluate the efficacy of ZnO NPs as antibacterial agents in fresh meat. The obtained results indicated that ZnO-NPs had a significant inhibitory effect on the growth of APC and Staphylococcus aureus during 6 days of refrigerator storage at 4 0C. At zero day, the mean values of APC in the control group was 3.27x107±6.05x106cfu/g, while after treatment with ZnO-NPs 5mM, 8mM and 10mM the mean values were decreased to 1.67x107±9.11x106, 1.55x107±9.73x106, and 9.41x106±7.67x105cfu/g, respectively. By the 3rd day of refrigeration storage the control group showed complete spoilage. While the mean values of Staphylococcus aureus at zero day in control group was 3.09x107±2.33x107cfu/g, while after treatment with ZnO-NPs 5mM, 8mM and 10mM the mean values were highly decreased to 1.40x107±9.56x106, 1.79x106±4.70x105, and 8.05x105±9.51x105cfu/g, respectively. Accurately, ZnO-NPs with concentration 10mM showed the highest reduction percentage 99.5% and 99.85% to APC and Staphylococcal aureus, respectively, from 3.27x107±6.05x106to 1.64x105±2.47x104 and 3.09x107±2.33x107 to 4.61x104±4.44x104 respectively, compared to other concentrations (5mM and 8mM). Thus the best sensory quality was obtained by ZnO-NP 10mM indicating to the fact that the antibacterial activity of ZnO-NPs is concentration dependent.