428 Bacteria in Relation to Cotmtry Life 



complished at the lower temperatures. Practical studies 

 on tlie ripening of American Cheddar cheese at different 

 temperatures have shown conclusively that at the 

 lower temperatures the ripening is more uniform, and 

 the keeping quality of the cheese much better. In fact, 

 ripening was shown to be experimentally practicable 

 at temperatures but little above freezing. Commercially, 



Fig. 65. Section through inflated and partly collapsed Emmenthaler 

 cheese. ( 1/5 natural size. Freudenreich.) 



however, this extension of the period of ripening has 

 its limitations. 



Cheese faults. — Abnormal ripening and the conse- 

 quent production of cheese that is not marketable, 

 occasion, at times, large monetary losses to the cheese- 

 maker. Among such faults, the most common is that 

 which leads to the formation of gassy curd. In this 

 case, large quantities of gas are generated by certain 

 gas-producing bacteria and the curd becomes filled with 

 cavities of various shapes and sizes. The surface of the 

 cheese bulges out, and, in extreme cases, the rind is 

 split open. Other abnormal characteristics, particularly 



