On the way home from the grocery, you get delayed so much that the frozen meat you’ve bought thaws out. The question for this Moment of Science is should you refreeze it? We’ve been told by reliable authorities that it’s not good to refreeze uncooked meat. Why not? If freezing the meat in the first place helps preserve it, why doesn’t this work the second time around? The answer to this question lies in the fact that all food has some bacteria in it, but normally not enough to hurt us. We freeze uncooked meat so that bacteria will not grow in it. But freezing does not kill all the bacteria that are already there, it just puts them in a kind of suspended animation. When the meat is thawed the bacteria come back to life and begin reproducing.