BUTTER 607 



abundance. As pointed out before, insufficient cooling of the 

 cream, especially after pasteurization, leaves the fat in a soft 

 condition. If this is not corrected by proper cooling the quality 

 of the butter suffers. 



If the butter is worked too much a physical change occurs in 

 the fat, which imparts to the butter an oily consistency. On the 

 other hand, insufficient manipulation makes the butter streaky 

 and the salt is not well distributed. Streaky butter may also re- 

 sult from mixing different lots of ripened cream before churning.- 

 The churning temperature should not be too high, otherwise the 

 fat becomes soft. About 55 F. is a good churning temperature. 



If the ripening process goes too far the casein precipitate is 

 hard and particles of casein become enmeshed in the fat. This 

 also occurs when hot water is added to sour cream to raise the 

 temperature. A cheesy taste is then imparted to the butter. 

 After churning at high temperature the butter may contain very 

 small drops of water in abundance and fat globules are then broken 

 up. The normally clear appearance of the butter is disturbed and 

 a cloudiness takes its place. In good butter the water is present 

 in relatively large drops. 



High temperature of ripening may produce abnormal flavors 

 by favoring the multiplication of Bacillus coli, B. ,subtilis, and 

 other bacteria which impart a bitter taste. A turnip taste is 

 ascribed by some to strains of B. coli. Lactose-fermenting yeasts 

 may also produce a bitter taste. If B. fluorescens remains in the 

 butter, either from unclean cream or water, the butter may soon 

 become rancid. This organism multiplies at relatively low tem- 

 perature. 



The influence of light in presence of oxygen produces rancidity 

 and decolorization of butter. It should, therefore, be protected 

 both from light and air by suitable packing. The keeping quality 

 of butter is then enhanced. Sufficient working to remove the 

 buttermilk and preservation in cold storage are important factors 

 for keeping butter in good condition. If it were possible to elim- 

 inate all bacteria except lactic acid bacteria, butter would keep 

 well for indefinite periods in the dark and at low temperature. 

 As it is impossible under commercial conditions to prevent some 

 contamination, decomposition may be expected. However, Rog- 

 ers, Berg, Potteiger, and Davis have found that at F. there is 

 no increase in soluble nitrogen for a long period. There was 

 probably no bacterial multiplication at this temperature, but 

 the authors found some evidence of proteolysjs caused: by 

 bacterial enzyms. They further found that butter from sweet 

 pasteurized milk keeps much better than butter made from raw 

 sweet cream. Rahn, Brown, and Smith found an increase of 



