42 Dairy Bacteriology. 



Influence of dusty air on germ life. 



Series A 16,000 13,536 12,216 12,890 15,340 



19,200 23,400 27,342 42,750 18,730 



Series B 483 610 820 715 1,880 



2,112 1,650 990 1,342 2,370 



These results indicate that the bacteria are in the main 

 attached to particles of considerable weight, as they settle 

 readily to the floor. 



It has long been observed that the milk of stall-kept 

 animals does not keep as well as that milked out-of-doors. 

 In some of the better sanitary dairies, it is customary ta 

 have a milking room, the walls of which may be kept 

 moist, or at least free from dust, and in this way eliminate 

 the effect of air infection. 



Relative importance of foregoing: factors. It is exceed- 

 ingly difficult to measure the relative values of these dif- 

 ferent methods of infection that have been cited, for they 

 are subject to so much fluctuation. Where the milk is 

 handled without any special care, unclean dairy utensils 

 and dirt from the animal are the most important sources 

 of pollution, not only with reference to the actual number 

 of bacteria introduced, but more particularly as to the effect 

 which bacteria of this class exert on the milk. If, how- 

 ever, careful supervision is given to the carrying out of ra- 

 tional methods of cleanliness, the most important factor 

 contributing to the germ content is often the fore milk. 



Sanitary or hygienic milk. By putting into practice the 

 various suggestions that have been made with reference to- 

 diminishing the bacterial content of milk, it is possible to 

 greatly reduce the number of organisms found therein, 

 and at the same time materially improve the keeping qual- 



