THE ADULTERATIOy OF DAIRY PRODUCTS 113 



large spoon with gentle heat. The process is has- 

 tened by stirring. The heat is then increased, the 

 material is brought to the boiling point and 

 thoroughly stirred. Oleomargarine and renovated 

 butter boil with much sputtering and produce no 

 foam, or very little, while genuine butter in boiling 

 produces more foam and less noise. The Water- 

 house test is conducted in the following way: " Into 

 a small beaker pour 50 cc. of sweet milk. Heat 

 nearly to boiling and add from 5 to 10 gm. of butter 

 or oleomargarine. Stir with a glass rod until the 

 fat is melted. The beaker is then placed in cold 

 water and the milk stirred until the temperature 

 falls sufficiently for the fat to congeal. At this 

 point the fat, if oleomargarine, can easily be collected 

 into one lump by means of the rod, while if butter 

 it will granulate and cannot be collected." 



105. Renovated Butter. — Low grade and rancid 

 butters are sometimes subjected to the process knowii 

 as renovation. The biitter is melted and poured 

 into cold water, so as to recrystallize the fat and 

 remove those products which impart the undesirable 

 flavors and odors. The butter fats are then re- 

 worked and salted, and the product is ready for the 

 market. It is often sold as fresh butter. Renovated 

 butter has poor keeping qualities, and so preserva- 

 tives, as boric acid, are frequently added to prevent 

 the fats from becoming rancid. When melted and 

 recrystallized, the butter fats fail to form crystals 

 of the same character as the original butter, which 



