194 BACTERIA IN BUTTER AND OLEOMARGARINE. 



is now largely prevented by a prohibitive tax on colored oleomarga- 

 rine. The bacteria normally present in oleo products are commonly 

 much less numerous than in butter, and the oleomargarine is, on 

 the whole, less likely to distribute infectious diseases than ordinary 

 butter, inasmuch as the chance for contamination is less. 



But, although the oleo products thus made resemble butter in 

 appearance, they do not resemble it in taste, and the factories are 

 therefore forced to use some special method of imparting to their 

 product a flavor as closely as possible like the butter which they are 

 trying to imitate. To do this they depend upon the very same flavors 

 as those found in butter and obtain them from a similar source. 

 A certain amount of whole milk, skim milk, or cream (varying 

 according to the quality desired in the product) is placed in a large 

 vat, or in cans, and allowed to sour. After the milk has properly 

 soured, or ripened, it is placed in the mixing vat with a quantity of 

 melted oils, generally in the proportion of about one part of milk to 

 four parts of the oils. When this mixture is hardened by the cold 

 brine, the milk is held with fats, and thus becomes a part of the 

 final product. Inasmuch as the milk has developed a flavor in its 

 souring, just as cream does during its ripening, this flavor is imparted 

 to the oleo product, and the final result is a mass of fats with the 

 flavor of butter more or less prominently developed. 



It is clear that this flavor is due to exactly the same factors as 

 those which produce the butter flavor. The oleo-maker fully 

 understands that his flavors are due to the action of bacteria, and 

 he uses the best means at his disposal to favor their growth. Ordi- 

 narily he allows his milk to sour by normal lactic fermentation. 

 In some factories, in recent years, he has not been satisfied to depend 

 upon such a method, but has come to use, more and more largely, 

 pure cultures of bacteria in order to introduce greater regularity in 

 the process. In some oleo factories, indeed, so fully aware have the 

 makers been of the extreme significance of this matter of proper 

 bacteria to the successful manufacture of oleo products, that they 

 have actually built and furnished bacteriological laboratories and 

 employed bacteriologists to keep constant guard over these factors 

 in the oleo-making. 





