THE RIPENING OF CHEESE. 241 



rule, to contain any one-sided predominating bacterial vegetation; 

 but this can only be secured if the milk has been obtained from 

 healthy cows, and if in the process of milking, as well as afterwards, 

 everything has been done in a clean and careful manner. If distur- 

 bances should arise in milk derived from different herds in a cheese 

 manufactory, and it be desired to discover from what herd the 

 milk which is unsuitable for cheese-making has been obtained, this 

 may often be effected by the application of the milk fermentation 

 test or the rennet test described in 33. 



It is by no means always easy or simple to conduct and regulate 

 the many different operations of cheese-making in such a manner 

 that the cheese manufactured from day to day will be of equally 

 good quality. Occasionally influences have to be dealt with which 

 defy all precaution; for example, the dealing with milk which is 

 unfit for the manufacture of cheese. It is therefore quite impossible 

 in cheese dairies, even in the best of them, to avoid turning out, 

 along with the more or less successful cheeses, a greater or less 

 percentage of failures. The causes which lead to failures in the 

 manufacture of cheeses, and which thus damage the cheese indus- 

 try, may be of very different kinds. Against a few of them there 

 is scarcely any safeguard. The most of them, however, and those 

 which are of most common occurrence, may be combated by the 

 exercise of the requisite amount of attention and skill. 



The commonly occurring disturbances and defects in cheeses are, for 

 example, as follows: 



(1) Those common to all sorts of cheeses. The cheese becomes inflated, 

 owing to the fact that the process of ripening takes place too soon, and 

 proceeds at too rapid a rate, a defect which may be generally, if not 

 always, overcome. 



(2) In soft cheeses the cheese runs, that is, it loses its shape, and is 

 changed into a sticky, gelatinous mass (refractory), a defect which is the 

 result of too quick ripening, and can always he avoided. 



(3) In soft cheeses the cheese becomes the prey of flies, which can 

 always be prevented. 



(4) In hard cheeses, the formation in certain places on the surface of 

 the cheese of fungoid growths, which convert the cheese into a dry white 

 powder, so that gradually larger or smaller holes are formed, beginning on 

 the surface of the cheese. This is always preventible. 



(5) In cheeses of all kinds, the occurrence in the cheese of a bitter or 

 a soapy flavour. This is a rare occurrence. 



( M 175 ) Q 



