I've had food poisoning SO many times that I'm always scared to eat things even a little past their prime.
That said I purchased organic hamburger last week, we made burgers that night. Two days later I put the remainder of the uncooked meat in the freezer. At that point it was slightly gray/greenish looking on the outside but the middle was still bright pink. Should I toss and start over? Right now it's still in the freezer.