Most of the dangerous bacteria get on the surface of beef during the slaughtering and butcheing process.
In the case of ground beef, the bacteria is mixed into the center of the mass of ground beef, and becomes difficult to kill. It doesn't breed faster or easier -- it's just more difficult to kill with cooking. Because of the temperatures, there is a significant possiblity that harmful bacteria created large enough populations to be dangerous in an part of the mass that cannot be rendered safe by cooking. Consequently the ground beef should be thrown out.
On the other hand, the rest of the meat is probably okay -- within limits. Yes, it's outside of FDA protocols, but ...
Don't serve to any of the "verys." I.e., very old, very young, very sick, and very sensitive. Don't serve to paying customers. Rinse the meat before using. Inspect it carefully. Cook to well done. Test it on your in-laws. You'll be fine.
The meat was cold when you got it and took some time to reach temperatures at which bacteria breed. The "forties" ruile is well and good, but bacteria breed more quickly at higher temperatures. It took awhile for even the surface of your meat get warm enough to get breeding going at a significant rate.
The meat was "vacuum packed." Well maybe not an absolute vaccum -- but low atmosphere, anyway. This does two things. Aerobic bacteria can't breed. Anaerobic bacteria can, but they leave a tell tale sign. They produce gas as a byproduct of activity and will cause the package to swell. Three other signs of a dangerously high level of bacteria are color, texture, and smell. If you notice anything wrong -- toss it.
It may not be "right," but it's real.