Swiss scientists say they've solved a problem many people may not have noticed: the disappearing holes in Swiss cheese. Researchers at a government agricultural institute say that contrary to a century of scientific belief, the holes are caused by hay particles, not bacteria, and modern milking is just too clean, the BBC reports. The researchers say that "microscopically small" flecks of hay that fell into milk-collecting buckets in barns helped the holes to form, and they were able to alter the number of holes in cheeses like Emmental by changing the amount of hay dust they added to milk, reports the AP.
Holes in Swiss cheese have been vanishing over the last 15 years, and the researchers say this is because modern industrial milking methods don't expose the milk to open barn environments, let alone dirty buckets, Swissinfo reports. The hole question has been around for a while: American scientist William Clark published research in 1917 stating that bacteria caused the holes to form, reports the BBC, which notes that the latest Swiss research hasn't been peer-reviewed, so other scientists haven't had a chance to find holes in it yet. (Another scientific food find: why popcorn goes "pop.")