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 domonstrated 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 glaucum, 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. 
* Towa Ex. Sta., Bul. 80. 
