Bacteria and Butter Making. 153 



renovating process. Old, soured, and stale cream is re- 

 duced in acidity by the addition of lime. The cream is 

 then pasteurized and aerated to expel the odors as much 

 as possible. A large amount of starter is then added 

 and the cream immediately churned. Under these con- 

 ditions, the bad flavors are materially reduced in intens- 

 ity, and desirable flavors absorbed by the fat from the 

 selected starter used. It is thus possible to produce but- 

 ter of good quality from cream that would at first be 

 regarded as quite unsuitable for butter production. 



In the manufacture of oleomargarine the same prin- 

 ciple is utilized. The butter aroma and flavor is im- 

 parted to the neutral oils and tasteless fats by mixing 

 the same with a properly prepared starter. Renovated 

 or process butter is given a desirable flavor in the same 

 way. 



Wash water. It has been found that the purity of 

 the water used in washing the granular butter has a 

 marked influence on the keeping quality. If the water 

 is from a shallow well into which surface water finds its 

 way, it is certain to contain large numbers of those types 

 of bacteria that are found in the soil, while if it -comes 

 from a deep well that is properly protected from surface 

 contamination, the bacterial content of the water will 

 be low and no injurious effect on the butter will be 

 noted. When it is impossible to obtain pure water for 

 washing purposes, a proper supply may be secured by 

 sterilizing the water. The most convenient way of heat- 

 ing the water is by the direct injection of steam. It is 

 necessary to use that coming directly from the boilers 

 and not the exhaust from the engine, since the latter is 

 likely to contain small amounts of oil that will impart to 

 the butter an objectionable flavor. After cooling, the 



