(Ruby Nguyen) The 21st century has not been kind to the trademark texture of Emmental cheese. To Americans, that’s Swiss cheese: the stuff with all the holes in. But the holes have been vanishing and the cheese becoming smoother over time. Scientists determined to find out why. The answer? Modern cheese is just too clean. The AP reports that a Swiss government-funded agricultural institute delved into the mystery of the nation’s most famous cheese and found that holes need hay.