One of the most common ways to tell if meat has gone bad is by seeing if it smells rancid and disgusting. That's usually the best indicator of bad meat. Examine the meat and see if it has a slimy texture. That usually means it's bad to eat. Also, if it's brown or kind of a gray color, then it's bad. It shouldn't be that color. Last but not least, you can always tell when meat is bad if it has a horrible taste.