162 Dairy Bacteriology. 



extreme types of the hard cheese are so dry and firm 

 that they can be cut only with difficulty. Such cheese 

 are used primarily as condiments to impart a flavor to 

 certain dishes, as macaroni, and for this purpose are 

 grated. The extreme type of soft cheese is a soft, pasty 

 mass and can be easily spread with a knife. 



Hard cheese, because the ripening process goes on uni- 

 formly throughout the entire mass of cheese, may be 

 made of any size which permits of commercial handling. 

 They can also be kept for long periods and preserve 

 their good qualities. Soft cheese are made in small sizes, 

 since on account of their consistency, they could not oth- 

 erwise be handled, and also because of the manner of 

 ripening. The ripening is due to the action of organisms 

 developing on the surface, the by-products of which dif- 

 fuse into the curd. If the cheese are too large, the outer 

 layers become overripe, while the interior remains more 

 or less unchanged, or insufficiently changed. Soft cheese 

 mature much more rapidly than hard cheese ; conse- 

 quently they are short lived. 



Although made from the same substance, milk, it is 

 noteworthy that there are over four hundred varieties 

 of cheese produced. Most of these find only a local 

 market where made. Less than a dozen varieties are to 

 be regarded as general articles of commerce. 



Quality of milk. In the making of butter there are 

 a number of processes that the maker can use when he 

 finds himself obliged to utilize poor milk. The milk 

 can be pasteurized and the harmful bacteria thus de- 

 stroyed; desirable kinds can then be added in the form 

 of a pure-culture starter. Pasteurization also drives off 

 some of the volatile by-products of the first acid fer- 

 mentation. By the use of these means, the maker can 

 prepare a very good product from poor material. 



