This is part of the reason why I wish we had more of an "open food" movement. As it stands, it is astonishingly difficult to make well reasoned choices about food. There are numerous gimmicks that can be played going far beyond things like http://www.simplemost.com/sneaky-reason-tic-tacs-can-say-sug... , which is still non-obvious.

This is a reason I added to my more "traditional" reasons for being a vegetarian - as it stands, it is very hard to reason about the likely supply chain of food that I purchase. Nevertheless, it is easier in my view with vegetables as they are lower down in the food chain. With meat, there are a whole bunch of extra parameters governing things beyond the feed composition and structure.

This also meshes well with the original ideas behind the virtues of free markets, which depend upon customers making informed, rational choices. "Openness" regarding the supply chain is essential for the critical "informed" aspect.