258 BUTTER-MAKING. 



and the condition of salt in butter vary so much at the different 

 creameries; they even vary considerably from one churning 

 to another at the same creamery. If conditions are uniform 

 in the creamery from day to day, the amount of salt to add 

 to butter, and the amount of salt retained in the butter when 

 finished, will be comparatively uniform. 



It should be mentioned in this connection that butter made 

 from very good cream should not be salted too heavily. Butter 

 made from a rather poor quality of cream may be salted corre- 

 spondingly heavier. This is due to the fact that the heavy 

 salty taste covers some of the undesirable flavors in the butter. 

 If the butter-flavors are good, they should not be hidden by 

 a heavy salty taste. If the butter-flavors are poor, then it 

 may be policy to partially cover them up with a medium-heavy 

 salty flavor. 



Effects of Salt upon Keeping Properties. That salt is anti- 

 septic is no longer a doubt. It has been demonstrated in 

 laboratory work with butter that the growth of certain germs, 

 isolated from butter, can be completely checked by the addi- 

 tion of a certain amount of salt to the medium in which they 

 are inoculated. Bouska * found that a yeast isolated from 

 butter showed luxuriant growth in a medium containing 2% 

 of salt in forty-eight hours, and only a trace in 4% of salt. 

 The same germ showed only a trace of growth in a 6% salt 

 medium after five days. 



The ordinary bread-mould, Penicillium ylaucum, was iso- 

 lated from butter and showed noticeable growth in a 9% Salt 

 medium in two days, and only a trace in a 10% solution during 

 the same time. A spore-bearing bacillus isolated from butter 

 produced only a trace of growth in a 4 ( /< salt medium. No 

 growth occurred at all in a medium containing 6% of salt. 

 Another gas-producing organism was also isolated from butter 

 and only a weakened growth was produced in a medium con- 

 taining 4% of salt. 



* Iowa Ex. Sta., Bui. 80. 



