You don't need to heat the milk. Take some plain ol' grocery store milk, hopefully organic (though organic, too, has its problems) and add some whey from Dannon's yogurt, or anything that has live cultures in it. If a probiotic capsule works, fine. The right kind can have more probiotic strains than yogurt has for example. Anyway, just set the milk out for 16-24 hours after you have added your probiotic. It will start to thicken up. When thick, eat. Of course save some for the next batch and on and on and it lives forever. So simple.
Whole milk works better than 2% or skim per my experience.