There is nothing bad about irradiated meat. FDA would not allow a process that would somehow hurt the people that consumed a product that had been irradiated. Irradiation to meat is like pasteurization is to milk.
Irradiation is marketed as an added food safety step, though it is actually the only real "kill" step for food-borne pathogens such as E. coli O157:H7 and Salmonella in ground beef. But the term "irradiation" is regarded by purchasers of ground beef as a guarantee that the ground beef they pick up at the grocery story is free of food-borne pathogens. Though the irradiation industry and proponents of the process have continued to stress the importance of safe handling practices such as the thorough cooking of irradiated product, some consumers, confident of the process's proven record of killing food-borne bacteria, have been known to undercook it in preparation.
For one, the beef industry has done much in the past few years to shore up its performance and reputation among consumers in the area of food safety. USDA Secretary Ann Veneman reported that, in random sampling by FSIS, cases of salmonella in raw meat and poultry had declined by 66% over the past six years and by 16% since last year. Just a few weeks ago, USDA announced data showing similar precipitous declines in E. coli O157:H7 in ground beef, and listeria in ready-to-eat meat and poultry products.