The aim of this study was to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) or/and lysozyme on the antibacterial activity of ovotransferrin against E. coli O157:H7. Ovotransferrin solution (20 mg/ml) containing 100 mM-NaHCO3 (OS) was added with EDTA (2.0 or 2.5 mg/ml), lysozyme (1.0, 1.5, or 2.0 mg/ml) or both were prepared. Antibacterial activities of OS (20 mg/ml ovotransferrin + 100 mM-NaHCO3), OSE (OS+ EDTA), or OSL (OS + lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. Also, OSE, OSL or OSEL (OS + EDTA + lysozyme) was applied on irradiated pork chops and commercial hams to determine if the solutions have antibacterial activity on meat products. The effect of initial cell population on the antibacterial activity of ovotransferrin and EDTA or lysozyme combinations was also determined. EDTA at 2 mg/ml plus OS (OSE2) induced 3 ~ 4 log reduction in viable E. coli O157:H7 cells in brain heart infusion (BHI) broth media, and 1 mg/ml lysozyme plus OS (OSL1) resulted in 0.5 ~ 1.0 log reduction during 35 ^oC incubation for 36 hr. However, OSE or OSEL did not show significant antibacterial effect on pork chops and hams during storage at 10 ^oC. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA (OSE) have potential to control E. coli O157:H7.