So, apparently a couple of years ago, Ohio passed a law banning milk producers from labeling their milk as free from rbST, a form of synthetic growth hormone given to cows to make them produce more milk. Unsurprisingly, the Sixth Circuit Court just ruled this unconstitutional on free speech grounds
What was more interesting to me was that the court went further, and ruled that milk from cows treated with rbST is compositionally different from milk from untreated cows. Which directly contradicts what the FDA said when it approved rbST for use.
Now, I've always taken the FDA statement about rbST at face value. I buy rbST-free milk, but I do so because a) it tends to be the default at most of the places I shop and b) I figure that farmers who pump their cows full of artificial hormones to maximize their milk production probably aren't farmers who prioritize the quality of their products or the well-being and happiness of their cows. I really assumed that the FDA was being absolutely truthful when it said there was no detectable difference. Which actually, given what I know about the FDA and the power of the dairy industry, seems naive.
Of course, there's no reason to take the court's decision as gospel either, given what a contentious subject this is. But it's kind of sad that this kind of question has to be fought out in the courts.