108 THE CREAMERY PATRON*S HANDBOOK. 



will warrant, still it should be thoroughly understood that this principle 

 does operate to a considerable extent and that undesirable or defective 

 milk is often produced entirely through the operation of these physical 

 processes. 



Many liquids have a great affinity for matter in a gaseous form and 

 will absorb varying amounts of such substances. These can be readily 

 recognized if the absorbed substance contains an odoriferous principle. 

 A fluid like milk possesses this property to an unusual degree, for not only 

 does the liquid serum absorb volatile odors, but the fat also has a great 

 affinity for many of these substances. 



ABSORPTION AFTER MILKING. 



As milk is exposed during the milking process and very often after its 

 withdrawal to an atmosphere that is liable to contain odors of an unde- 

 sirable character, it is not surprising to note that it may thus contract 

 flavors by direct absorption. The peculiar stable odor is due to the vol- 

 atile products that are escaping from the decomposing masses of manure 

 or fermenting foods and the exhalations from the bodies of animals in the 

 barn. Under ordinary circumstances the barn air is saturated with these 

 products, and even in a well ventilated barn, where considerable care is 

 taken to purify the air, they persist to a greater or less degree in spite of 

 all efforts. 



It is a popular belief that* milk will not absorb any of these odors if it 

 is warmer than the surrounding air; that it exhales odors when warmer 

 and absorbs odors only when colder than the atmosphere. For this reason 

 it is said that there is no danger of milk absorbing any taints in the barn 

 so long as it is removed from such an atmosphere before it is cool. Scarcely 

 any one will uphold the method of leaving milk in the barn over night as 

 a process that is consistent with a pure sweet product; yet, owing to this 

 popular notion concerning the absorptive properties of milk, a large major- 

 ity of dairymen believe that the exposure in the barn air is fraught with 

 no particular danger so long as the milk is removed before it loses its natural 

 heat. 



While the popular belief expressed above is throughly entrenched 

 in the minds of many dairymen, still, it is contradicted by the every-day 

 experience of the housewife. The careful housekeeper has learned by 

 experience that milk or even meat should not be put into a refrigerator 

 in a warm condition. It should first be allowed to cool before being placed 

 in such a confined atmosphere, for, when warm, it absorbs more readily 

 any odors that may come from other foods, and is thus tainted much sooner 

 than would be the case if it were chilled before being placed in the refrig- 

 erator. 



Experiments made by the author where milk was exposed to air sat- 

 urated with various volatile odors showed that both warm and cold milk 

 absorbed these odors in less than an hour to such an extent that they could 



