REPORT OF THE BACTERIOLOGIST. 
THE EFFICIENCY OF A CONTINUOUS PAS- 
TEURIZER AT DIFFERENT TEMPERA- 
TURES.” 
H. A. Harpineg anp L. A. Rogers. 
SUMMARY. 
These tests were made by passing mixed whole milk through a 
Danish continuous pasteurizer. At 70°C. (158°F.) the efficiency 
of the continuous pasteurizer varies greatly from day to day. 
Tests upon 14 different days gave an average of 15,288 living 
germs per cubic centimeter left in the pasteurized milk, with a 
maximum of 62,790 and a minimum of 120 germs. 
At 80° C. (176° F.) the reduction in germ content is both very 
uniform and very great. Tests upon 25 different days gave an 
average of only 117 living germs per cubic centimeter in the 
pasteurized milk, with a maximum of 297 and a minimum of 20 
germs. 
At 85° C. (185° F.) the average reduction is not more marked 
than at 80° C. but the range of variation is less. This temperature 
has the added advantage, according to Dr. Bang, of removing the 
danger from germs of tuberculosis in the milk. 
Even when the whole milk was heated to 85°C. the butter did 
not have a permanent cooked flavor. 
INTRODUCTION. 
An inquiry into the laws which underlie any of the complex 
commercial processes will progress slowly if each step is deter- 

* Reprint of Bulletin No. 172. 
