RENNET CHEESE FROM SHEEP'S MILK. 261 



and should not be interrupted. Certain gas-generating bacteria, which are 

 always present in the byre, in the food, in the udder of the cow, and in 

 dairies, occasionally in enormous quantities, should not be wanting in 

 milk which has to be made into cheese, but they should not be permitted 

 to choke out other kinds of bacteria. 



Lately it has been discovered that the preparation of Emmenthaler 

 cheese is facilitated if the milk which has to be treated possess a certain 

 definite degree of sourness, neither too strong nor too weak, and that it 

 is desirable where this sourness is lacking to increase it by the addition 

 of sour whey. The quantity of lactic ferment which, as experience has 

 taught, produces the proper degree of sourness, seems to regulate in a bene- 

 ficial manner the growth of the gas-producing bacteria, by limiting them 

 when they are in excessive quantity, but not exercising an unfavourable 

 influence when they are present in small quantity. If the manufacture 

 of the cheese gains in security by the addition of small quantities of sour 

 whey to the milk, it loses on the other hand, it would appear, in fineness of 

 flavour. 



Puffy cheeses have irregularly distributed cavities as large as the fist, 

 and exhibit a more or less disfigured external appearance, assuming in the 

 course of time a peculiar soapy flavour. Very often the swelling of the 

 cheese begins on the surface; and often a few hours after the preparation 

 of the cheese it becomes puffy, when the ordinary gas-forming bacteria 

 choke out the other bacteria, or when strange ferments are present which 

 give rise to a fermentation in which there is a development of gas. This 

 occurs most frequently where the milk to be treated is dirtily handled, 

 and feeding-stuffs have been used which contain such fungi. Puffiriess 

 is favoured by faults in the preparation and treatment of cheese, which 

 result in too much moisture remaining behind in the cheese mass, such 

 as using too weak rennet, thickening at too low a temperature, insuffi- 

 cient stirring, too quick warming, careless straining of the curd, insufficient 

 pressure, carelessness in pressing, unskilful salting, and too high a tempera- 

 ture in the air of the store-room. Puffiness in the cheese, in the opinion 

 of the author, is in most cases caused by fission fungi, and not by budding 

 fungi. The gases produced in puffiness, in addition to carbonic anhydride, 

 are large quantities of hydrogen. 



122. Rennet Cheese from Sheep's Milk. Cheese from sheep's 

 milk is prepared wherever sheep are kept on a large scale. It is 

 made in small quantities, and for consumption in the neighbourhood 

 of the place of manufacture. Only one kind of cheese made from 

 sheep's milk, viz. the famous Roquefort cheese, made in France, is 

 placed on the world's market. 



