It might also be useful to know that as raw milk sours (which it might do, even with all your care) it is still useful. You can use it in pancakes or quick breads; its an essential ingredient in Irish soda bread. It is, in other words, still good stuff. Pasteurized milk, on the other hand, does not sour well, it just gets horrid.
http://www.keeperofthehome.org/2009/04/dont-cry-over-sour-milk-using-your-raw-milk-gone-bad.html
http://www.keeperofthehome.org/2009/04/dont-cry-over-sour-milk-using-your-raw-milk-gone-bad.html