That implies a whole other set of dirty tricks available - not only "laundering" products but using it to libel competitors or as a protection racket of sorts. Fungible commodities are a very awkward thing to differentiate, much less trace and proving that there is no basis is hard, especially if there are other counterfeit packagers.

If "Foo Fish" really uses only Pacific Cod but I find a package with Atlantic Cod printed and packed identically how can you prove a disregard for the truth or bad intentions in saying "Foo Fish contains lying mislabeled fish?" I sourced the fish from this store from this wholesaler with the same packaging.

Introducing PPKI could technically help but would be a logistical nightmare and vulnerable to copying.