Holes that form in cheeses such as emmental caused by hay particles in milk and not CO2 released by bacteria, say experts
![Mice are not the culprit either.](https://i.guim.co.uk/static/w-300/h--/q-95/sys-images/Guardian/Pix/pictures/2015/5/28/1432824968833/0446a1d8-9b17-4163-8aa8-e38f3a359ee3-300x180.jpeg)
After about a century of research, scientists in Switzerland have finally solved the mystery of the holes in Swiss cheese.
Despite what you may have been told as a child, the holes are not caused by mice nibbling away inside cheese wheels.