I think you should have said milk may include antibiotics, growth hormones and preservatives. It depends on where you get your milk. In Canada where you are from you should not worry about antibiotics or growth hormones in your milk supply for they are both illegal there. As for preservatives, well they are just about everywhere and in everything.
I think you are wrong, our farmers are apologizing for using antibiotics, but says "it's necessary," the only thing I know to be illegal here, is the hormone used to produce 50% more milk, and only because the scientist studying it went public with their findings, much to the chargrin of the government.