Post-packaging irradiation combined with modified atmosphere packaging can effectively reduce E.coli O157: H7 in ground beef patties, and Listeria monocytogenes on cooked pork chops and frankfurters. The irradiation sensitivity of these two food-borne pathogens was found to be similar in both vacuum and low oxygen MAP packaging. However, E. coli O157:H7 can survive irradiation in both vacuum and low-oxygen MAP packaging during storage, therefore, temperature-abused or undercooked irradiated vacuum or MAP packaged ground beef may not be safe. MAP with 100% CO2 was effective for extending the lag phase of Listeria monocytogenes survivors on irradiated ready-to-eat meat products up to 10 to 11 weeks. MAP packaging with low oxygen and 0.4% CO can be used for stabilizing fresh meat color when the product is treated with irradiation, which often results in discoloration.