The study that Pat Bull and I did originally on bm at room temperature demonstrated that there was no statistical difference between bacterial composition of bm at room temp (75 to 78 degrees) and that of refrigerated bm at 10 hours. In fact, in some of the cultures, the room temp bm had less bacteria than it's counterpart that was refrigerated after 10 hours. Would that change if the bm was left in a baking hot room or in the sun? What effect does heat have on it? I don't know. Would it make a difference if it was 11 hours instead of 10? The same goes for refrigeration -- what magical thing happens to bm at the 73rd hour (or the 49th or the 25th depending upon which theory you subscribe to) that makes it unfit for baby consumption? What if it smells & tastes OK? Is it then OK, regardless of how long it has been out/refrig/frozen? How many permutations of a study have to be done for it to be acceptable? How long do we recommend formula to be left out? What if a mom carries a bottle of formula in her diaper bag all day long for her baby? Do we tell her that is unacceptable and that the risks of the baby getting sick are very high? We should be. Formula has NO antibacterial factors to prevent multiplication of bacteria. Yet what do the less compliant moms do with their formula? Is it better for them to keep bm out for longer periods of time or formula? Lots of questions, no answers..... does anyone out there have them? (The answers - I have all the questions =)!!) Jan B.