James JO Smith.. age 11 of Allentown  Penna.. for his questions

Are the holes in Swiss cheese necessary?

In order to make Swiss cheese  the cheese‑maker must make a trade with a tiny bacterium. The little creature is far too small to be seen$ but he has been given a sizeable name. perhaps in honor of his hard work. He is known as Propionibacterium Helveticium. We will call him P. H. for short„

P. H. and countless numbers of his small relatives are given their favorite food and their favorite climate. Their food is milk ‑ sweets. fresh milk. Rennet is added to the brew and the milk curdles. The curd is cut into small pieces and heated to a high temperature.

Later it is left to drain dry. This treatment suits the host of little bacteria. They eat and eat and multiply and multiply in the process they give off certain gases. The gas cannot escape through the hardening cheese. So it collects in round balloons. These balloons og gas cause the holes. or eyess present in the Swiss cheese.

It is impossible to make Swiss cheese without the help of little P.. H. aril his relatives„ They cannot do the job without giving off quantities of gas. So  it seems. the round holes in Swiss cheese are absolutely necessary.