Dairy Queen is one of the largest fast food systems in the world, established in 1940. Based in Jeannette, Pa., the company has more than 5,900 restaurants in the United States, Canada and 20 foreign countries. In 1998, Berkshire Hathaway Inc. acquired International Dairy Queen, Inc. and its subsidiary companies. Dairy Queen's menu comprises cheeseburgers, hot dogs, chicken wraps, regular...