Page:Popular Science Monthly Volume 40.djvu/795

Rh first made, cheese is soft and tastes somewhat like milk curd. It has none of the palatable taste which we find in the cheese of our table. It is a long ripening which gives this taste to the cheese.

Here, again, the ripening process is one of bacteria growth. The millions of bacteria that were in the milk are stored away in the cheese, and instead of being killed here, as they are in the butter, they begin to multiply immediately. Here, too, there is a battle of bacteria, and now one species is in the ascendency and now another. If the wrong species gets the upper hand, the cheese becomes bad, and cheese-makers have their greatest trouble from this source. The bacteria do not grow so rapidly as they do in cream, for the conditions are less favorable, but the ripening is kept up for months, and during the whole time the bacteria are growing. Under their action the character of the cheese slowly changes. Here, again, the decomposition products are responsible for the taste and odor. In some cases, such as Limburger cheese, the action is allowed to continue to the verge of putrefaction. Ordinarily it is not continued so far, but in all cases the cheese-maker favors the growth of certain forms of bacteria by regulating the temperature at which the ripening is carried on. As the ripening continues, certain parts of the cheese are digested and decomposed by the bacteria growth, and, as the products of decomposition accumulate, the taste grows stronger. After a time it is considered fit for the market, but the longer the ripening continues the stronger the taste becomes.

Little is known yet as to the bacteriology of different kinds of cheeses. Whether the different tastes of Edam, Limburger, and other characteristic cheeses is largely due to the character of the bacteria ripening them can not yet be said. Cheese-makers do, however, have much trouble with various irregular forms of ripening, and a great drawback in this business is the lack of uniformity in this respect. Beyond doubt this is due largely, perhaps chiefly, to the variety and number of bacteria which succeed in gaining a foothold in the cheese and contribute to its ripening.

Along the line of cheese manufacture our bacteriologists are promising us help from their researches. Of course, the cheese maker has never paid any attention to the sort of bacteria which he plants in his cheeses, for he has never heard of them. Sometimes he has unwittingly planted species which produce violent poisons, as is shown by the many instances of death from eating poisonous cheese. Now, our bacteriologists are suggesting that the ripening of cheese may be easily controlled. Artificial cultures of the proper sort may be furnished the cheese-maker, and if these are planted in the cheese not only will the danger from poisonous cheese be prevented, but at the same time the desired taste of the cheese be assured. More than this, when we recognize