BACTERIOLOGICAL STUDIES OF MILK 

 SUPPLIES OF BOULDER, COLORADO^ 



FIRST PRELIMINARY REPORT^ 



By Clough Txtrrill Bxtrnett 



I have on many occasions been questioned regarding the purity 

 of Boulder's milk supply, so often, in fact, that it has seemed advisable 

 to make a rather careful investigation of the milk as delivered by the 

 various wagons and milk depots. This work was begun without any 

 idea of making an extensive report and such a report^ is impossible 

 at the present time. 



The examinations cited extend over a period of eighteen months, 

 comprising two sets of examinations during the summer months and 

 one set made in the winter of 1909 and 1910. In all cases the milk was 

 obtained as nearly under normal conditions as possible. If the sample 

 was from a wagon it was rushed to the laboratory immediately on 

 delivery and examination begun at once. 



Twenty-one samples were studied up to September i, 1910. Of 

 these, examination was begun on two, two hours after milking, on 

 one, four hours after milking, on thirteen, five hours after milking, 

 on two, seven hours after milking, on two, eight hours after milking, 

 and on one, fourteen hours after milking. In each case this was the 

 earliest time under existing conditions that the consumer could use 

 the milk. That is, in the thirteen samples examined five hours after 

 milking, these milks used were not available until that time; and no 

 matter what the bacterial count may have been immediately after 

 milking, if it was high when delivered, the milk should be condemned 

 or looked upon with suspicion. 



Immediately on being received at the laboratory the milk, after 

 proper cleansing of the mouth of the bottle, was poured into two sterile 



' From the Laboratory of Bacteriology, University of Colorado. 

 ' Read before the University Scientific Society, February 27, 1911. 



» A careful study of the dairy situation in Boulder is in progress, the work being carried on by a student 

 in the Graduate School. 



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