76 STORRS AGRICULTURAL EXPERIMENT STATION. 
Tables 14 and 15, which precede, give the results of the studies 
made upon butter. 
It will be observed that there is a constant decrease in the 
number of bacteria as the butter becomes older. In general 
this decrease is most marked at the very outset. In the case of 
the first lot of unsalted butter 65 per cent. of all the bacteria 
present died off in the first day. Ripened cream contains im- 
mense numbers of germs, hence it would be expected that 
freshly churned butter would also contain large numbers. After 
a number of days the number of bacteria are in general smaller 
in the inner than in the outer portions of the butter. 
SUMMARY. 
The number of bacteria in milk increases very rapidly with the age — 
of the milk, This increase ts most rapid when milk ts kept warm, 
as warmth ts favorable to the growth of the organisms. “Cooling 
milk as rapidly as possible and keeping at a low temperature hinders 
the development of the germs. 
The number of bacteria in milk as ordinarily sold may vary from 
thousands to millions per cubic centimeter. The smallest number 
found in milk sold in Middletown was eleven thousand per cubic 
centimeter and the largest number was nearly eight and a half 
millions. As there are 946 cubic centimeters tn a guart, these 
figures mean that the milk had from ten million to eight billion 
(eight thousand million) bacterta per quart. 
The presence of only a small number of bacteria tn milk indicates 
care and cleanliness in tts handling and storage and also that tt ts 
comparatively freshly drawn. Sour milk and ripened cream contain 
many millions of bacteria in a cubtc centimeter. 
The number of bacteria in butter, whether salted or unsalted, 
gradually diminishes as the age of the butter increases. In butter a 
year old the number becomes very small indeed. There ts a more 
rapid decrease of bacteria in butter during the first few hours than 
1s exhibited later and there ts a more rapid decrease in the inside of 
the butter roll than on the outside. The decrease in salted butter ts 
much greater in the first few hours than that of unsalted butter. 


