78 Dairy Bacteriology. 



with a sieve of such construction that the bottles will drain 

 thoroughly if inclined in an inverted position. 



Interpretation of results of test. The curd from a good 

 milk has a firm, solid texture, and should contain at most 

 only a few small pin holes. It may have some large, irreg- 

 ular, ''mechanical 1 ' holes where the curd particles have 

 failed to cement, as is seen in Fig. 19. If gas-producing bac- 



Fto. 19. Curd from a good milk. The large Irregular holes are Hiechanical. 



teria are very prevalent in the milk, the conditions under 

 which the test is made cause such a rapid growth of the 

 same that the evidence of the abnormal fermentation may 

 bs readily seen in the spongy texture of the curd (Fig. 20). 

 If the undesirable organisms are not very abundant and the 

 conditions not especially suited to their growth, the " pin 

 holes " will be less frequent. 



Sometimes the curds show no evidence of gas, but their 

 abnormal condition can be recognized by the "mushy" 

 texture and the presence of " off" flavors that are rendered 

 more apparent by keeping them in closed bottles. This 

 condition is abnormal and is apt to produce quite as serious 

 results as if gas was formed. 



