206 AGRICULTURAL BACTERIOLOGY 



a great improvement in farm butter could be made by a 

 more perfect control of the ripening process, which could 

 be easily attained by the use of starters. Small quantities 

 of starters can be made in such vessels as fruit-jars or 

 milk-bottles. 



Flavor of butter substitutes, Oleomargarin is made 

 from fats that are devoid of butter flavor. If this product 

 is to be sold as a butter substitute, the butter flavor must be 

 developed. This is imparted to. the product by churning 

 the fats with sour milk. The flavor of the oleomargarin 

 is thus identical in origin and nature with the flavor of 

 butter. Renovated butter is made from a poor quality 

 of butter, the flavor of which is of low grade or decidedly 

 below standard. The fat used in its manufacture is 

 melted, and the obnoxious flavors are removed by passing 

 air through it, and by washing the fat. The desirable 

 flavor is then imparted by churning the fat with some 

 milk soured by pure cultures of bacteria. In the manu- 

 facture of oleomargarin and renovated butter, the most 

 approved scientific methods are employed to impart to the 

 otherwise neutral fats the characteristic flavor that is so 

 much in demand in the butter market. 



Decomposition of butter. Butter deteriorates more or 

 less rapidly, depending on the kinds of bacteria present in 

 the cream and on the temperature at which it is stored. 

 The best keeping butter is that made from sweet cream that 

 has been pasteurized; the poorest keeping butter is that 

 from a raw, sweet cream or from a sour cream that contains 

 not only great numbers of undesirable flavor-forming bac- 

 teria, but yeasts and molds. If the butter is stored at 

 ordinary temperatures, the development of undesirable 

 flavors is rapid, while at the temperatures maintained in 

 butter-storage rooms, below zero F., the changes are very 

 slow. If the butter is kept in small packages, so that a 



