44 Dairy Bacteriology. 



of this sort can easily be prevented by taking care that 

 dairy stock is not fed such feed. 



46. Straining" milk in the barn. For convenience, 

 milk is often strained in the barn, but the danger of 

 tainting the same where this is done is so great that the 

 custom is not to be recommended. In straining the milk 

 so much surface is exposed to the air that considerable 

 bacterial infection can occur, unless this is carried out in 

 a room free from all dust particles. Where the process 

 is done in the barn, the can with its strainer is often left 

 uncovered. Under these conditions, a constant deposi- 

 tion of germ life is taking place, and with every pailful 

 of milk strained, this is washed through the meshes of 

 the strainer into the milk below. 



47. Absorption of odors in fresh milk. Not only 

 is straining in the barn to be deprecated from the above 

 standpoint, but the possibility of direct physical absorp- 

 tion of existing taints in the stable should warn one 

 against this custom. It is a commonly accepted idea that 

 milk evolves odors and cannot absorb them so long as it 

 is warmer than the surrounding air, but from experi- 

 mental evidence, l the writer has definitely shown that the 

 direct absorption of odors takes place much more rapidly 

 when the milk is warm than when cold, although under 

 either condition, it absorbs volatile substances with con- 

 siderable avidity. In testing this, fresh milk was ex- 

 posed to an atmosphere impregnated with odors of 

 various essential oils and other peculiar aromatic sub- 

 stance, whose odors could be readily identified. Under 

 these conditions the cooled milk was tainted very much 

 less than the milk at body temperatures, even where the 

 exposure was for a half hour. 



Russell, 15th Kept. Wis. Expt. Stat., p. 104, 1898. 



