Once upon a time, a great many years ago, I was serving in Korea and had a task (some heavy lifting) with which some strong young Korean lads assisted. As a thank-you and a treat, I went to the club on the army base and got a couple of pizzas to go. When I returned with Cokes and pizza, the boys were aghast. They loved the Coca Cola, but they asked me, as they sniffed the pizza, how I could eat something that had rotten milk on it.