The “first rule of food safety” is: KEEP IT CLEAN. The average field dressed deer when it makes it to the garage or to camp site is never nearly as clean as it could be, yet there a few things you can do to help improve its cleanliness and subsequent safety (remember, deer can harbor the same pathogens as beef cattle and other meat animals, including E. coli O157:H7). It’s very unlikely that the deer carcass will ever be free of pathogenic or spoilage bacteria, which is why temperature is so very important to evaluate (unfortuntely, if left hanging, you may not be able to control its temperature until the venison is cut,wrapped and frozen/refrigerated). Rule number two: KEEP IT COLD. Ideally, the ambient temperature in which a deer carcass can hang and undergo minimal bacterial growth is 40°F and lower. If kept at or below 40°F, it is recommended that the venison be cut and packaged within 48 and no longer than 72 hours. The warmer the temperature, the much shorter the time that buck or doe can “hang out.”
It’s not a bad idea to engage a few other safety strategies beyond keeping it cold. Washing the carcass can remove visual debris (hair, blood, etc.) and bacteria (E. coli, Salmonella, etc.), but remember that one of the things that bacteria just love is moisture. Ensure that the carcass can dry at or below 40°F. To mitigate any bacterial contamination, beef processors apply a weak organic acid solution to the carcass, primals, subprimals and trim to kill any bacteria (this is achieved by a temporary pH reduction on the meat’s surface). You can do this, too, with the help of some household vinegar. Store-bought white vinegar is about 3% acetic acid, which is known to kill many bacteria. Simply fill a clean spray bottle with vinegar and spray the vinegar on the deer carcass. One critical point to remember when applying vinegar to the carcass is to wait a bit (5-10 minutes) after washing with water so the carcass is somewhat dry. If applied when wet, the vinegar would (1) be diluted to an ineffective level and (2) likely drip away with the excess moisture. After spraying with vinegar, let the carcass dry (still at 40°F or below) before cutting.
Much of the information above is intended to be a “best case scenario.” When possible, incorporate as many of these concepts as possible to minimize the risk of food borne illness due to the consumption of tainted venison.