I've had a vacuum packed brisket that I bought about 4 weeks ago in my fridge. I just noticed today that it is getting quite a bit of air in it. Almost as if it had sprung a leak. I've tried rotating it around all over and none of the blood leaks out anywhere, so I think it is actually still sealed. I don't see any signs of discoloration. I'm going to let my nose be my guide when I open it this weekend. Anyone else have any experience with this?