I was buying milk at the grocery the other day when I realized a habit of mine. There's always "newer" milk mixed in with the older milk, y'know? There's milk that's due to spoil a week from today and some that's got ten days before it's unfit to drink, and sometimes you'll find one that only has a mere three days left before instantly turning into a big curd. Well, I always seem to take the "freshest" milk I can find, that is, the one with the most time left. I assume I'm not alone in this practice, and I got to wondering, what happens to the gallons and gallons of milk that aren't purchased? I can't imagine they are just poured into a big sink somewhere. Do they recycle it into something like pig slop?

-- King Dairy, the net

A while ago we grappled with the question of the shelf life of milk products and determined that the sell-by date on milk isn't the day the bacteria take over and gob up the product. It's assumed the product will sit in your fridge and be drinkable for another week or so. But, yes, I'm sure most people shuffle cartons around looking for the freshest, not that it matters. So the lonely, rejected gallons are pulled from the shelf after the sell-by date. What happens then depends on the whim of the vendor. Most of it is returned to the processor, who stores it in a separate facility, away from the new product, then sells it to recyclers who make -- would you believe it -- pig slop. The rest is poured into a big sink somewhere. Unsold fluid milk can't be used to make any other (human) food product. And even milk sold for pig food is carefully checked for bacteria count before it's accepted. So if you're upset by the waste, then take pity on those sell-by rejects.