768 Popular Editions of Station Bulletins of the 



ments give an average of about 75 more germs in the milk of the 

 cows after they had been clipped than before. This would seem to 

 indicate that clipping cows increases, rather than decreases, the prob- 

 ability of germs finding their way into the milk during the milking 

 process. The data certainly do not support the prevailing idea 

 that clipping the udders and flanks of cows is a valuable aid in the 

 production of sanitary milk. 



Reasoning on general principles, it is quite 

 Hand and logical to assume that the vacuum cleaner would 

 machine milking prove as effective when applied to the coats of 

 of cows cows as it is in the household and many depart- 



ments of business. The use of such an apparatus 

 is quite feasible where the milking machine is installed since a 

 vacuum pump is used in connection with the milker. Such a method 

 of cleaning has been recommended by the American Association 

 of Medical Milk Commissions. In a careful series of tests made in 

 our stable, the germ content of the milk was not reduced by the use 

 of the vacuum cleaner and more time was needed to go over the cows 

 than when currycomb and brush were used. Some difficulty was 

 met with at first in securing what seemed to be an effective vacuum 

 and comparative tests made under these conditions showed a dis- 

 advantage, even in the germ content, in the use of the vacuum cleaner. 

 When arrangements were made, by which the vacuum of approxi- 

 mately one-half an atmosphere could be regularly maintained, the 

 differences in germ content between hand cleaning and machine 

 cleaning practically disappeared, but, as stated before, the time 

 required for each animal was greater with the machine than when 

 cleaning by hand. Our results, as a whole, do not seem to justify 

 the purchase of a vacuum cleaner for use in the cow stable. 



In all of these tests the bacterial counts of the 

 When do bacteria milk as drawn were very low and changes in stable 

 enter the milk? conditions seemed to exert no measurable influ- 

 ence upon the number of these organisms present. 

 This raised the question as to what are the important sources of 

 bacteria in milk. 



Accordingly, on 17 days the germ content of a pail of milk was 

 followed from the cow through the various operations in preparing 

 it for the consumer. At the Station, the milk is taken to a small 

 milk room, separated from the stable by a single door, poured over an 

 aerating cooler, collected in a second pail and taken in this to the dairy. 

 Here it is passed through a cloth strainer into a third pail in which 

 it is placed in cold water until needed. All these utensils are cleaned 

 with hot water and sal soda and treated for ten to fifteen minutes 

 in a steam box. The cooler was not protected in any special manner 

 during use, though the milk room was kept moderately clean. 



Samples were taken which represent the stoppings, and the milk 

 in the pail, after leaving the cooler, after arriving at the dairy, and 



