This should come naturally while going for the other massively time consuming achievements in the game.
Tainted meat is created with uncooked meat + devils puffball
After you find a wolf, run back to the raft. carefully walk out and chuck the tainted meat near the wolf. preferably throw it directly on top of one. it will eat the meat and die. repeat 20 times for the achievement.
Tainted meat is used in the later part of playthroughs because it is the easiest way to kill wolves and consumes the least amount of resources. This holds true because eventually you'll have so much jerky and cooked meat that you'll just end of spoiling the meat instead of using it. I've noticed sometimes tainted meat can be used again if picked up by the player after you kill the wolf with it the first time.
Eventually you'll start encountering 3 wolves at a time which makes this very easy. I finished my campaign playthrough and had killed 10 wolves this way. Seems hards, but in the later end of your playthrough you'll end up doing this a lot.