PRODUCTION OF MILK OP LOW BACTERIAL CONTENT. 



METHOD OF SAMPLING AND MAKING THE BACTERIAL COUNT. 



After milking, the cans of milk were promptly carried from the 

 barn to the milk room, a distance of a few hundred feet, situated in 

 the same building as the laboratory. Long-handled white-agate 

 dippers, cleaned between milkings and sterilized just before using, 

 were used to stir the milk and to take the sample. A separate dipper 

 was used for each sample, and the milk was poured carefully into 

 sterile pint bottles, which were immediately closed with sterile caps. 

 The fact that the 

 laboratory was 

 in the same build- 

 ing made it pos- 

 sible to pour the 

 plates within one 

 lour after milk- 

 ing. The same 

 routine was fol- 

 lowed at both 

 morning and eve- 

 ning milkings, 

 regardless of how 

 the other factors 

 varied. Since 



the 

 tion 



mterpreta- 



of results 

 depends partly 

 on the nature of 

 the medium and 

 on its subsequent 

 incubation it is 



necessary to State ^ IG " ^" — ^e small ~ to P P ai l used in the experiments. 



xactly how the counts were obtained. For the sake of uniformity 

 ^Iain-extract agar, prepared according to the revised recommenda- 

 ions of the Committee on Standard Methods of Bacterial Milk 

 ^.nalysi's, 1 was used. The plates were incubated for five days at 

 >0° C. (86° F.) and counted with the aid of a hand glass of three 

 tnd one-half diameters magnification. 



THE EXPERIMENTAL WORK. 



In the experiments the plan was to begin with conditions in which 

 he barn and cows were as filthy as possible. When those conditions 



1 Rochester meeting of American Public Health Association, September, 1915 (Commit- 

 ee on Standard Methods). 



