rBST is a naturally occuring hormone that cows produce anyway. There is NO test that will show if rBST has been used by the dairy person.  rBST  IS NOT transfered by the milk to the person..  There's more here,  but,, pay close attention to the very end of the article, who the person is and who pays her wages for what she does.

http://www.articlesbase.com/health-articles/sorting-through-the-issues-of-organic-milk-212117.html