I once read that some adventurer's club back in the day got ahold of some mammoth/mastadon meat from an animal that was dug up out of some glacier. They promptly threw it on the grill and had a big cookout. Word is that while the meat was still safe to eat, it tasted rotten due to age. See, while deep-freezing meat will keep it from spoiling and growing bacteria that is harmful to humans, simply freezing the meat won't prevent the muscle tissue from breaking down over time. In order to prevent that from happening, you'd probably need to be able to get near absolute zero temperatures.