So I usually buy irradiated beef. From what I understand, the beef is packaged, sealed, and the absolutely blasted with radiation. I'm a nuclear engineer for a living, so I know that most things tend to die when exposed to the levels of dose that this beef is subject to. Normally food spoils by having bacteria and mold and such munch away on it, but here, all of that should be dead.
If its perfectly sealed away, and there's nothing living inside the package, how can it spoil?