Some St. Louis Style Ribs sold in stores are injected with a salt solution and other flavorings to keep the meat moister, and it also adds some additional weight to the product. Not sure exactly how they do it, but somehow, it never leaves a mark in the meat. And I can attest to the fact that they are juicier and work great for the Traeger 3-2-1 cooking method. Not to mention, they actually taste pretty good and are easier to cook perfectly as well. Ribs labeled as "Natural" or "minimal processing" are not injected. You have to read the fine print otherwise to determine if they have been.