V&M has used pork fat for years. Here's some of their advertising I got off Land Big Fish.com I can't find a site for V&M.
ATTRACTANTS: OK, sure they smell, but once again it's simple: non only are fish not blind, but they can smell and taste, too. Early on we discovered that Pork Fat cooked into every V&M bait not only attracted fish but made them hang onto our baits longer. The process of actually cooking the pork fat and other ingredients in the bait means that fishermen are assured that they are getting the right amount of attractant on every bait, plus there's none of this spraying or squirting in. Fishermen go fishing to fish, not spend their day treating bait with an attractant that eventually washes off anyway.