100 FOOD SUBSTITUTES AND ADULTERANTS 



oils. Milk fat is scattered through the milk in the form of tiny 

 globules, but if the milk is allowed to stand undisturbed these 

 globules rise to the surface and can be skimmed off as cream. 

 When milk or cream is vigorously shaken or stirred, as in churn- 

 ing, these globules strike each other, adhere, and form larger 

 and larger masses of fat or butter. As soon as the fat has 

 collected in a large mass, it is removed from the buttermilk, is 

 washed, worked, salted, and colored. 



The flavor of butter depends upon bacteria; butter made 

 from sour cream has a distinct flavor because of substances 

 produced by the bacteria which changed the sweet cream to 

 sour cream. Butter made from sweet cream would lack the 

 agreeable flavor unless it was added in some way. The flavor 

 of sweet cream butter is secured by putting bacteria into the 

 sweet cream before agitating it. The kind of bacteria and 

 their number can be regulated in the creamery, and hence the 

 taste can be varied somewhat to suit the purchasers. 



Butter that is carelessly made and handled becomes rancid 

 and unfit for use. It is then remade or renovated and sold as 

 fresh butter. If a test tube containing a piece of butter is 

 placed in hot water, the butter melts and the fat rises and floats 

 as a clear yellow layer on the top ; the casein or curd in the 

 butter collects as a whitish mass beneath the fat, and the briny 

 water settles to the bottom of the tube. When butter becomes 

 rancid it is put in large tanks and melted, and strong air cur- 

 rents are blown through it to remove disagreeable odors. The 

 whole mass is then cooled ; the clear, odorless fat layer on the 

 top is removed, mixed with fresh milk, and rechurned. Such 

 renovated butter or butterine is less desirable than fresh 

 butter, and many states protect the public against it by 

 requiring labels on the package. But labels are often of 

 little value because many people do not know what renovated 

 butter is. 



