THE HARD CHEESES. 2OI 



and inoculated into the milk, and the use of commercial starters is 

 also rapidly growing. It is interesting to find that the types of lactic 

 bacteria that are useful in butter-making are not always satisfactory 

 in cheese-making. Bacteria that give a fine flavor and aroma to 

 butter may produce a bitter taste with ruinous results when used 

 in cheese-making. The use of starters in the cheese industry seems 

 to be firmly established at the present time and is practically sure 

 to extend, for it is one of the methods of safe-guarding the cheese 

 against undesirable fermentations. 



"Faults" in Hard Cheese. The value of a cheese is wholly 

 dependent upon the success of the ripening. A great loss is entailed 

 upon cheese-makers by an imperfect ripening, resulting from a 

 variety of defects called faults. These are commonly due to the 

 growth of certain kinds of microorganisms which do not grow in 

 normal cheeses. The injury resulting to the cheese may be only 

 sufficient to make the cheese a little "off" in flavor but still passable, 

 or it may be so great as utterly to ruin the cheese and make it a total 

 loss. Some of these faults have been traced to their sources and 

 will be considered under the following heads: 



Swelled Cheese. This is, perhaps, the most common fault. 

 It is due to the development of a considerable quantity of gas which 

 fills the curd full of holes and causes it to swell and 

 lose its shape. Sometimes the holes are extremely 

 numerous and small, and sometimes they are fewer CD 



but of larger size. In any case they are undesir- 

 able. Even good cheeses are apt to show some gas 

 holes, but so few as to do no special injury. Some- bacillus causing 

 times the gas is so abundant as to cause the *,v e i} e S. heese 



(B. Shaft eri). 



cheese to burst, in which case it is completely 

 ruined. Between these extremes are all kinds of intermediate 

 grades. The development of the gas is accompanied by an unusual 

 fermentation and an unpleasant taste and smell. The cause 

 of the trouble is the development of gas-producing bacteria. Several 

 different species are known which have this power of developing 

 gas in great quantities in the ripening cheese (Fig. 43). Most of 

 them, perhaps all, belong to the type which has been referred to 



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