CHURNING 301 



varying considerably with the kind of feed, the breed of cows 

 and the period of lactation. The Channel Island breeds produce 

 a more highly yellow butter than the Holsteins and Ayrshires, 

 and at the beginning of the period of lactation the cream and 

 butter have a deeper shade of yellow than after the cows have 

 been in milk for some months. All green feeds and yellow roots 

 intensify the yellow color of butter while most dry roughage, 

 grains and mill by-products tend to diminish the yellow color 

 of milk and dairy products. (See also "Color Defects of Butter," 

 Chapter XVII.) 



In order to maintain uniformity of color, or the color of 

 summer butter, throughout the year, in fall, winter, early spring 

 and in times of drought during the summer, butter is artificially 

 colored. For this purpose a variety of butter colors is used. 



A suitable butter color must be free from ingredients injuri- 

 ous to the health of the consumer, it should have such strength 

 of coloring that only a very small quantity need be added to 

 cream in order to give the butter the desired shade of yellow, 

 and it must be free from undesirable odors and flavors so as 

 to not impair the quality and market value of the butter. 



Aniline colors which formerly were used extensively for 

 this purpose possess very intensive coloring properties, but 

 their use is prohibited by the Federal Pure Food Act which 

 went in force in 1907. 1 While extracts from various plants 

 may serve as butter colors, the bulk of butter color of com- 

 merce today is the coloring substance extracted from the seed 

 of the Annatto plant, Bixa oreltana, by means of some neutral 

 oil, such as cottonseed oil, or corn oil. 



The extract of butter color is made by boiling the annatto 

 seed in the oil for several hours. During the latter period of 

 the process the heat is raised to a very high temperature, about 

 240 degrees F., for the purpose of effecting a permanent solu- 

 tion of the annatto coloring principle in the oil. The mixture 

 is then filtered through heavy canvas, either by gravity or un- 



1 On January 9, 1920, the IT. S. Department of Agriculture, Bureau of 

 Chemistry, S.R.A.-Chem. 24, announced the certification, subject to the pro- 

 visions of Food Inspection Decisions 76, 117 and 129, the following oil-soluble 

 coal-tar dies: Yellow A.B. (Benzeneazo B naphthylamine), and Yellow 

 O.B. (Ortho-Tolueneazo B naphthylamine). These two coal-tar dies can 

 now be legitimately used as butter colors. 



