BUTTER DEFECTS 471 



associated, their prevention must of necessity lie -with the pro- 

 ducer of milk and cream. The flavors due to weeds such as gar- 

 lic, rag weed, etc., can be guarded against only by eradication of 

 these weeds from the pasture. See "Garlic Flavor." 



Roots, such as turnips, are best fed after milking in order to 

 give the feed time to pass through and out of the cow several 

 hours before the succeeding milking. 



Feed flavors caused by frozen, decayed and moldy feed are 

 prevented by eliminating from the ration all feed not in good, 

 sound condition. Sour, moldy silage, frozen and decayed roots 

 and tops of roots, damp, moldy and poorly cured hay, damp and 

 musty straw, etc., should not be fed to dairy cows. 



While most of the feed flavors are inherent in the milk and 

 cream which contain them and therefore follow these products 

 into the butter and while their appearance in the butter is beyond 

 the control of the great majority of creameries, many of these 

 flavors, not including the garlic flavor, and rag weed flavor, are 

 greatly minimized by pasteurization and aeration of the cream. 

 Pasteurization assists in driving and expelling from the product 

 volatile flavors, odors, and gases and thus helps to lessen the in- 

 tensity of these flavors in the finished butter. 



Garlic or Wild Onion Flavor. When the wild onion flavor 

 has once impregnated the milk or cream, it is very difficult to keep 

 this objectionable flavor out of the butter, and butter made from 

 such milk or cream usually grades a poor "Seconds." It may be 

 improved materially, however, by blowing air through the milk 

 or cream while hot and by prolonged pasteurization at a high 

 temperature. Ayres and Johnson 1 demonstrated that milk and 

 cream can be freed from the wild onion flavor entirely by ade- 

 quate blowing, while these raw materials are hot. These investi- 

 gators contrived a blowing equipment for blowing milk and cream 

 on a small scale, with which they were able to entirely remove 

 the onion flavor from milk heated to 145 F for five minutes. For 

 cream they recommend a somewhat longer period of blowing and 

 a temperature of 160 F. Their work was done with sweet cream 

 testing 30% fat. It is probable that for richer cream and for 

 cream that is sour, the apparatus devised would have to be modi- 



1 Ayres and Johnson, Removal of Garlic Flavor from Milk and Cream, 

 U. S. Dept. of Agr., B. A. T. Farmers' Bulletin 608, 1914. 



