180 Defects of Milk. 



and render slimy either the entire milk, or the casein is precipitat- 

 ed and only the whey develops a strong tenacious, stringy 

 consistency. 



The cause of the slimy condition may be produced either by 

 a slimy change of the sugar, which is accomplished with the form- 

 ation of a high molecular weight body, the galactan or the viscose, 

 or by the swelling of the bacterial capsules which form a mucin- 

 like substance. 



The best known producer of slimy or stringy milk is the Strep- 

 tococcus hollandicus, the cause of the "long whey," which is con- 

 sidered by Weigmann as a degenerated streptococcus of lactic acid 

 fermentation. If cultivation of the producer of the "long whey" 

 is continued at 35 deg. C. it loses the property of producing slime, 

 and changes into a lactic acid producer. 



From various groups of bacteria the following have been 

 proved to be slime producers: Bacterium lactis longi a strep- 

 tococcus in Swedish thick milk (Troili Petersson), Micrococcus 

 (streptococcus) viscosus (Schmidt-Muhlheim), Micrococcus mu- 

 cilaginosus from slimy cream (Ratz), and Streptococcus burri 

 from stringy whey. 



Slime is further known to be produced by the colon-aerogenes 

 group (Emmerling, Schardinger), the Bacillus guillebeau, as well 

 as the Bacillus lactorubefaciens. Adametz, Duclaux, Gruber, 

 Ward, Eckles, and Marshall have also isolated slime producers 

 from milk, whey, food substances, straw, stable air, and spring 

 water. 



Other defects of milk which are associated with change of 

 consistency (and color changes), are produced by milk drawn from 

 affected udders, which subject has been discussed in the section 

 on "Diseases of the Udder." 



Considering the living requirements of the special varieties of 

 bacteria, the defects of milk appear to be especially frequent under 

 certain weather conditions and in certain periods of the year. 

 Thus the milk dealers of Munich complained of the appearance of 

 defects of taste, especially in the cool and cold period of the year, 

 and at the time of changing the animals from stable to pasture 

 feeding and vice versa. The cause may lie in the fact that with the 

 beginning of the dry, that is stable feeding, the microbian flora of 

 the intestinal canal and of the forage and the stable air is different 

 from that existing during the period of pasture feeding, and 

 thereby other species of bacteria, aroma producers, contaminate 

 the milk; likewise in certain cold climates and in certain methods 

 of keeping milk the bacteria, excepting the lactic acid producers, 

 find just the requirements which aid them in their propagation. 



In 1909, the following defects of milk were found among 1,000 

 samples examined monthly: 



