Bacteria and Butter Making. 151 



soon as gas-forming bacteria are introduced, trouble is 

 likely to result. 



In the propagation of starters, it is always to be re- 

 membered that the bacteria, although invisible to the 

 eye, are living things, and unless conditions are favor- 

 able in every particular, it is impossible to keep them 

 in a healthy condition, so that growth in the cream is 

 rapid, producing the acid demanded for churning, and 

 imparting to the butter the desired flavor, both as to 

 degree and kind. No part of the daily routine of the 

 butter maker should be performed with more care than 

 the preparation of the starters, both the mother starters, 

 and the larger one for addition to the cream. The latter 

 can best be made in one of the many forms of starter 

 cans now on the market, since by their use, the maker 

 can heat and cool the milk with little trouble, and can 

 maintain the starter at a^iy desired temperature. Bet- 

 ter starters cannot be made in them than by the use of 

 simple and improvised apparatus, but better results can 

 be obtained with the same expenditure of time and labor. 



In the handling of the large starter, care should be 

 used not to overripen, since the larger quantity is more 

 likely to "whey off" than is the smaller starter. Skim 

 milk rather than whole should be used for this. It 

 should be selected with care and heated to 200 F. for 

 thirty minutes. When it is impossible to secure fresh 

 milk for starter making purposes, either condensed skim 

 milk or milk powder may be used. The condensed milk 

 is diluted with water until its volume is about the same 

 as the milk before concentration; the mixture is then 

 treated the same as fresh milk, being heated and cooled 

 before inoculation. In the case of milk powder, one 

 part of the powder is added to ten or twelve parts of 



