 Because once any cereal is prepared from the original grain, or the grain is processed by any kind of milling, the oils will be oxidized and go rancid day by day. And the perishability of the oils that are ingrained once they've been milled is even greater than the perishability of raw milk. I mean, every bakery should be required to grind their own flour at the time of baking for any product made from cereal sources.