Why Cheeses Has some Holes?

Cheese is important food that made from milk and a lots of people consume it. It is estimated there are more than 3000 kinds of cheese worldwide.

And this is the story why cheese has some holes

Cheese usually found in Swiss state, holes in the cheese is caused by propioni bacteria. The Bacteria are generally used in cube cheese, Limburger, and Liderkanz. This bacteria provide sweet taste for cheese. Cheeses made from acidified milk. The acidifying process is helped by yeast and bacteria. When the cheese is in the preservation step, propioni bacteria sort out some gasses. Bubbles from these gasses who causing rounded holes on the cheese.

Because these holes that make Swiss cheeses looks unique.

- sorry if there a mistaken spells or grammars, cause iam indonesian -