Bacteria in the Cheese Industry. 179 



cheese changing the casein into a soft slimy mass. Then, 

 again, the interior of the cheese undergoes this slimy de- 

 composition. The soft varieties are more prone toward 

 this fermentation than the hard, although the firm 

 cheeses are by no means exempt from the trouble. The 

 verlauf en " or " running ' ' of limburger cheese is a 

 fermentation allied to this. It is where the inside of the 

 cheese breaks down into a soft semi-fluid mass. In se- 

 vere, cases, the rind may even be ruptured, in which case, 

 the whole interior of the cheese flows out as a thick slimy 

 mass having sometimes a putrid odor. The conditions 

 favoring this putrid decomposition are usually associated 

 with an excess of moisture, and an abnormally low ripen- 

 ing temperature. 



188. Pigment changes in cheese. Occasionally 

 with hard cheeses, but more often with the softer foreign 

 varieties, abnormal conditions are noted that express 

 themselves in the production of various pigments in 

 the different sorts of cheese. The production of these 

 variously colored pigments are due mainly to the action 

 of bacteria, yeasts, -and molds. More frequently they are 

 merely superficial, and affect only the exterior layers of 

 the cheese. 



1. Rusty cheese. This difficulty has been the source 

 of considerable trouble to makers of white or un- 

 colored cheddar cheese in some sections of America. It 

 is characterized by the appearance, especially in July and 

 August, of rusty red or orange spots that are noted 

 throughout the interior of the cheese, particularly along 

 the edge of the curd particles. Council 1 traced an out- 

 break of this sort in a Canadian factory to defective 

 drains, and succeeded in isolating a red chromogenic 



1 Connell, Kept, of Com. of Agric. and Dairying, part xvi; p. 14, 



1898. 



