In Europe we can barely stop people from selling horsemeat as beef. I'm not sure how effectively we are implementing any of these rules, and I'm sure a farmer who wishes to do so can flout them at will.
One positive thing to come from the rise of supermarkets and chains is that their own brands suffer when their suppliers fuck up. They alone have the power to police their producers. And we see this in this article with McD's et al pushing for higher standards.