174 THE BOOK OF BUTTER 



should be clear and not milky. From the bacteriological 

 viewpoint, the buttermilk should be washed out so that 

 the bacteria will be depri\'ed of it as a food. According 

 to Jensen/ lactic acid bacteria were found to multiply 

 much more rapidly in unwashed than in washed butter. 

 This was not true of some of the other types. It is need- 

 less to say that the wash water should be practically free 

 from germs. McKay and Larsen ^ advise the use of one 

 of two methods of treatment when the water is impure ; 

 i.e. pasteurization or filtration. They seem to consider 

 pasteurization more complete. One of their conclusions 

 follows, " Butter made from pasteurized cream and 

 washed in pasteurized water retains its normal flavor 

 about twice as long as butter made from unpasteurized 

 water." Melick ^ asserts that there is a direct relation 

 between the bacterial-content of the wash water and the 

 keeping quality of the butter. He found that a filter 

 for creamery water is likely to be only a source of con- 

 tamination. He considers that it is both practical and 

 economical to sterilize wash water for washing butter, 

 and he adds that the water should be cooled and used 

 immediately, for otherwise the practice is a useless expense. 

 However, it seems that it should be of value if the water 

 is properly protected from contamination. 



131. Effect of acidity on flavor of storage butter. — 

 Usually when butter is said to be in storage, it is assumed 



1 Jensen, O. A., Bacteriological Study of Danish Butter. 

 [Rev. G6n. Lait. 8 (1910), No. 18, pp. 409-417 ; Centbl. Bakt., etc.] 

 2 abt., 29 (1911), No. 23-25, pp. 610-616; Molk. Ztg. Berlin, 21 

 (1911), No. 18, pp. 205-207; Exp. Sta. Rec. 216, p. 478. 



^ McKay, G. L., and Larsen, C, The Keeping Quality of 

 Butter, la. State Col. Exp. Sta., Bui. 71, p. 30, 1903. 



3 Mehck, C. W., Effect of Bacteria in Wash Water of Butter, 

 Kan. Agri, Col. Exp. Sta., Bui. 138, p. 222, 1906. 



