Lees hieronder het transcript:

Swiss cheese, those types of cheeses, have holes in them which are known as eyes because they are made to produce them.

My name is Michael Tunick, I am a research chemist for the US Department of Agriculture. I wrote the book “The Science of Cheese.”

The kind of bacteria that’s in them produce something called propionic acid. And as they do, it also produces carbon dioxide gas, and those little bubbles of carbon dioxide gas collect. And the curd, which hasn’t hardened up completely, those form these eyes inside of the cheese. There are some varieties of cheese which are made to have those eyes in them.

Gruyere is another one which will have smaller eyes to them but most cheeses don't have those in there. You may see some little slits or holes or openings in there and that's just because of air as the curd is pressed, but it's the Swiss type cheeses or Emmental type cheeses are the ones that have those holes or eyes in them.