XIV.] THE RIPENING OF CHEESE 287 



3. Certain moulds, such as Penicillium, the blue 

 mould of cheese, begin to grow in the curd, and these 

 likewise split up the casein and the butter fat, forming 

 from them bodies possessing strong flavour and smell. 

 The particular set of organisms which will develop in 

 any make of cheese depends entirely upon the processes 

 of manufacture, and in many cases upon the actual 

 place in which the manufacture is carried out. The 

 walls and the vessels of dairies which have for a long 

 time been devoted to the manufacture of a particular 

 kind of cheese become impregnated with the organisms 

 associated with that cheese and communicate them to 

 the new curd. Furthermore, the many details in the 

 management which experience alone has taught the 

 cheesemaker, can be shown to bring about the 

 encouragement or depression of particular groups of 

 organisms which affect the flavour of the resulting 

 cheese. The curing process is also accompanied by a 

 gradual shrinking of the cheese and an expulsion of the 

 whey which is still contained in the curd. For this 

 reason it is necessary to change the cloths surrounding 

 the cheese rather frequently at first, and to turn the 

 cheeses constantly when they have been put into the 

 storage-room. It is also necessary to maintain the 

 storage-room at the constant temperature which 

 experience has shown to be appropriate to the develop- 

 ment of the special flavour of the cheese. As the 

 manufacture of cheese is thus dependent upon the 

 development of particular groups of organisms, it is clear 

 that it may very easily be turned in a wrong direction, 

 should any of the encroaching putrefactive or otherwise 

 undesirable organisms, which are abundant in dust, 

 dirt, foul water, etc., establish themselves in the curd. 

 It is to these intrusive organisms that defects in the 

 flavour or texture of cheese are usually due, and they 



