CAROTIN, THE PRINCIPAL YELLOW, P^tfMEN'rpf Miiac FAT. 315 



A REVIEW OF THE LITERATURE CONCERNING THE YELLOW 

 PLANT AND ANIMAL PIGMENTS. 



It has been the custom for generations to judge the quality of 

 dairy products to a large extent by their yellow color. This has been 

 carried to such an extent that the manufacturer of butter, whether 

 it be on a large or small scale, finds it impossible to market butter that 

 does not have a standard yellow color. The consumer of milk or cream 

 as a rule looks upon a yellow color as indicating the richness and quality 

 of the product. Although it is well known that the color has no 

 relation to the food value of milk or cream, the popular prejudice 

 is so strong that the producer of market milk has to take it into 

 account and try to supply a product with as much natural yellow 

 color as possible. 



During part of the year, namely during the spring and early 

 summer and usually also in the early fall, the fresh green feeds which 

 the cows receive give the shade of yellow to the milk fat which the 

 consumer demands. During the winter months, or in summer if the 

 pastures become dry, this yellow color is wholly or in part absent 

 from the milk fat, and the butter manufacturer is then forced to 

 color the butter artificially, in order to maintain the required standard. 



It is generally accepted as a fact that the breed of the cow has 

 a pronounced relation to the color of the milk fat and that the Guernsey 

 and Jersey breeds rank first in this respect. The breeders of this class 

 of cattle have emphasized this characteristic as one of the strong points 

 of their respective breeds. This characteristic of Guernsey and Jersey 

 breeds, as compared with the Holstein and Ayrshire breeds, has been 

 generally attributed to physiological differences. According to this 

 view, Guernsey and Jersey cattle are able to produce a higher colored 

 fat due to some inherent quality, just as they are able to produce a 

 higher percentage of fat in their milk. It is a well-known fact that 

 the skin and the secretions of the skin of Guernsey and Jersey cattle 

 have a higher yellow color than other breeds, and this characteristic 

 is looked upon by cattle breeders as an indication of the ability of 

 animals of these breeds to produce highly colored milk fat. 



The body fat of Guernsey and Jersey cattle is also characterized 

 by a high yellow color and for this reason beef from these animals 

 is often looked upon with disfavor by the butcher and the consumer. 



That the yellow color of butter has a relation to its market value 

 is shown by the fact that "color" has a place on the standard butter 

 score cards with a value of fifteen out of one hundred points. The 



