Unless You Take Yours With Milk

I don't get why orange juice has to be refrigerated. I mean, I understand why you would WANT to keep it cold, because it's way more delicious that way. But I want to know why you can't keep it outside of the fridge with the cap on tight for like 2 days, and then put it in the fridge and drink it after that.

Actually, I'm basing this whole post on the assumption that the "KEEP REFRIGERATED" warning on the side of the carton is an order, as opposed to a suggestion. If a reader who is in the citrus growing industry could help me out with this, that would be great. Julius, I'm looking at you...

(I don't actually know a Julius, but I figure that if I knew someone who worked with oranges, I'd want to call him Julius.)