I researched and worked with aging meat for a few years. I would age my 12 & Up whole briskets 45 - 50 days from the kill date shown on the side of the case. These briskets were placed in a dedicated commercial refrigerator set on 36 degrees. I probably cooked 250 - 300 aged briskets. In all that time, only once did I have a bad brisket and it was my fault.
Here are some tips I learned. Watch the gas bubbles in the cry-o-vac. When they go from being very small to about dime size, it's time to cook or freeze that brisket. If they get to quarter size, it's time to cook that brisket today! Always, always, always go by the kill date when aging brisket. Also, if you're going to stretch wet aging to it's limits (50 days), the more you know about how that brisket was treated before it made it's way to you, the better. On refrigerator temps, anything below 35 degrees is preserving/prolonging the meat, not aging it. Ideal temps are 35 - 37 degrees. The refrigerator in your Kitchen is a bad choice. Aging meat requires a stable environment. The temperature fluctuations associated with opening the door on your fridge, even once a day, is not good for aging meat.
One note on smell, when you open the package of a 45- 50 day wet aged brisket, it will have a distinct beefy musky smell, but it won't be in any way offensive. A bad brisket has a sharper, sour smell. There is a big difference.
Above all else, be careful. Nobody wants to make someone sick with bad meat. When in doubt, throw it out. It just isn't worth it
