Father, Mike Sr., came to the U.S. in 1914, settled in Colorado. Whipped up homemade mozzarella and ricotta cheese for local customers in 1950s. Son Jim joined company at 18; turned modest family business into world's largest mozzarella producer. Today Leprino Foods operates 11 plants around U.S. and Europe. Sales: $2.4 billion. Leprino cheese baked into Dominos, Papa John's, Pizza Hut pizzas; also ingredient in Hot Pockets, string cheese. By-products whey protein, lactose, sweet whey powder used in infant formula, yogurt. Plans for new plant in Colorado.