Dee Dee Gehl, age 14, of Columbus Ohio for the question:
How do they make cheese?
Limburger, Camembert, Cheddar, Edam, Brier Parmesan, Swiss, Tilsit and Roquefort are names of different cheeses. There are hard cheeses, soft cheeses and good old yellow cheese so handy for baiting mouse traps. There is an endless variety of cheeses and no excuse why a tasty nibble of this valuable food is not on everyone’s daily diet.
All cheese is made from milk. Most of our cheeses are made from cows milk, and some are from goats milk. In some countries good cheese is made from camel’s milk, llama’s milk and even from sheep's milk. But no one could make cheese from milk without help. And the help comes from, of all places, the world of microbus. The real job of turning milk into cheese is done by hosts of tiny bacteria.
Cheeses were made before anyone knew that bacteria existed. Most of our cheeses wore developed before we knew the role of bacteria in cheese making. The different cheese names are so often place names because a certain cheese could be made in only one locale. This was because the active bacteria were different in various regions.
About 100 years ago, some Swiss cheese makers went to Tilsit, East Prussia, to make Swiss cheese. The pasture was good, the cows were healthy and the milk was rich. The same recipe for making Swiss cheese was used. But the finished cheese was soft, white and had little slits instead of the familiar big round holes. The bacteria necessary for making real Swiss cheese were not present in the milk of East Prussia.
Even a pint of pasteurized milk contains billions of assorted bacteria. Each different cheese recipe destroys some and encourages others. The milk is first curdled to separate the solids from the liquids. For cottage cheese, the milk is curdled with acid. For hard cheeses it is curdled with rennet ‑ which is junket powder.
In making cottage cheese or cream cheese, the solids are cut up, heated and drained. The cheese is then ready to be eaten. Large, hard cheeses take longer to make. The cheese needs time to the soured milk into solid cheese of the right texture. ripen. The bacteria must have time to impart their flavor and transform
The milk solids of the soured milk are called the curd. The curd is sliced into bits with a wire cutter. To make soft, tangy Camembert, the curd is heated just a little. To make hard Swiss cheese it is heated slowly to a high temperature. The solid curd is packed into boxes lined with cheese cloth and left to drain. Limburger is rubbed with salt to make a tangy rind. Rocquefort is mixed with mold or moldy bread.
Our wonderful scientists can tell which bacteria make which cheese. The cheese maker no longer depends on chance to make his recipe. He uses pure cultures of the special bacterium he needs. The fellow that makes those round holes and the special flavor of Swiss cheese is named Propionibacterium helveticum ‑ a very big name for a very tiny fellow. When a pure culture of this bacterium is added to the milk or the curd Swiss cheese can be made in Tilsit or any other part of the world.