624 MILK 



Roquefort cheese, and are ripened by lactic acid bacteria and a 

 green mold. 



Brie and Isigny are cheeses similar to Camembert cheese. 

 The curd is prepared much as is the Camembert curd, but the 

 micro-organisms concerned in the ripening process are different. 

 These cheeses have not been studied to a great extent and the 

 microflora has not been precisely determined. The French Brie 

 cheese is ripened by groups of micro-organisms similar to those 

 producing Camembert, but the American product is quite different. 



Cheese made from goat's milk has a darker color than most 

 other cheeses, and has a strong odor and taste which appeal to 

 the tastes of some people. 



Abnobmal Cheese 



One of the most frequent abnormal forms of cheese is gassy 

 cheese. Gas formation militates against good taste and appear- 

 ance. Gassy cheese may have either too many small holes or a 

 few very large ones. Manurial pollution of milk or old rennet 

 are responsible for gassy cheese in most instances. Gas formation 

 is caused by lactose fermentation caused by members of the 

 Bacillus coli group of bacteria or closely related bacteria, as, for 

 example, the organism described by Moore and Ward, which 

 not only produced a gassy cheese but also a taint. Bacteria of 

 this group are rarely present in the udder, but can be found in 

 nearly all milk after it has been drawn. If present in large num- 

 bers, as in dirty milk, they may gain ascendency over lactic acid 

 bacteria unless these are scarce. Heating of the cm-d, pasteuriza- 

 tion of the milk, and salting of the curd are preventive measures. 

 Sammis has found that in the presence of lactic acid bacteria the 

 gas produced by the Bacillus coh group is retained in the curd, 

 while in the absence of lactic acid bacteria most of the gas formed 

 escapes. Doane and Eldredge canie to the conclusion that gas 

 formation is prevented by the presence of Bacillus bulgaricus, 

 but not that of the common lactic acid bacteria. 



The Wisconsin curd test (see page 210) is especially designed 

 to aid the cheese maker in determining the quahty of milk as 

 regards possible gas formation. The curd may appear chiefly in 

 flve types, as follows: 



1. The curd remains fluid with a sweetish or slightly bitter--' 

 taste, or but slightly sour with a bitter taste. This happens 

 when exceptionally clean milk is used and results from interaction 

 of Streptococcus lacticus. Bacillus coli or B. aerogenes, and 

 various micrococci. 



2. The curd is gelatinous and may show streaks of gas. A 

 smooth gelatinous curd is due to action of Streptococcus lacticus. 



