68 PRACTICAL DAIRY BACTERIOLOGY 



tions. Every different vessel or utensil with which the milk 

 comes in contact, on its way from the cow to actual consump- 

 tion, adds its quota of bacteria. 



Probably the various vessels and utensils supply the largest 

 source of milk bacteria. 1 The great difficulty of keeping these 

 clean leaves them almost filled with bacteria. As the milk 

 passes from the cow through one utensil to another it gathers 

 more and more bacteria. For example, in a rather badly kept 

 dairy the following figures were found by Bergy: 



Number of bacteria in milk from udder 400 



Number of bacteria in milk in bucket 800 



Number of bacteria after passing strainer ... . 60,000 



Number of bacteria after passing cooler 34,ooo 



Number of bacteria in tank below cooler 173,000 



Number of bacteria after passing bottler 84,000 



While these numbers do not regularly increase they do show 

 that there is a growing contamination from the various utensils 

 with which the milk comes in contact. The irregularities in the 

 results are doubtless due to the difficulty of getting average 

 samples, always a great difficulty in such analyses. 



The Milker. Of late years it has become more evident that 

 the bacteria from the milker or other persons in the dairy are 

 among the most serious. This is not so much because of the 

 number of the bacteria that may enter the milk from this source 

 but of their types. In ordinary dairies the milker rarely makes 

 any special toilet before milking, and is liable to perform this 

 task in old, soiled clothes, with no special attempt at cleaning 

 his hands or face. Under these circumstances, while he is not 

 so great a source of bacteria as the cow, some of these organ- 

 isms are sure to fall from his hands or clothing into the milk 

 vessels. The number of bacteria from such a source is, probably, 



!Erf. and Meleck. Bui. No. 131, Kan. Exper. Sta. 1905. 



