Swiss cheese with holes. Swiss cheese is a generic term for cheeses such as Jarlsberg, Havarti, Maasdam, or Fontina. These are all cheeses with holes, or eyes. The holes are created by the bacteria that change milk to cheese. Propionibacterium freudenreichii uses the lactic acid which is produced by other bacteria, and produces carbon dioxide gas; the gas slowly forms bubbles which, as the cheese hardens, are solidified. The holes of the cheese are called the eyes, and a Swiss cheese that does not have holes is called a blind cheese. The factors that make the eyes larger, longer maturation and higher temperature, make the taste and quality of the cheese better too.