The smell of bad deer meat is the most obvious indicator of spoilage. Deer meat that is spoiled will have a pungent odor when it is thawed. Some say it smells of sewage. During the cooking process, the smell will become even more pungent and does not dissipate. The entire home or cooking area will begin to smell badly.
After the deer has been killed, inspect the animal and log how long the deer sat before being dressed. The information will be pertinent when using the meat for consumption.
Assume any meat that has been in the refrigerator or cooler for more then three days to be suspect. Inspect the meat to ensure the color and texture is normal.
Check the meat's surface to ensure it is not slimy or otherwise slick. The meat should be smooth but not wet.
Smell the meat. If the meat smells extremely pungent, much like sewage, you can assume that it is no longer good and cannot be used. While venison has a distinct smell, it should never smell bad. It should smell gamy, but a smell of sewage or vomit indicates the meat is bad.
Cook the meat. Spoiled meat will become more pungent as it is cooked, not less. If the meat smells worse as it is cooked, you can assume that it has gone bad and should not be eaten.
Frozen deer meat can be good for two years or more when kept in a freezer. Freezer-burned meat should tossed.