86 DAIRY LABORATORY GUIDE 



well and pour into a petra dish. The solution will 

 then contain .01 c.c. of milk, and the number of 

 colonies that develop in the petra dish is therefore 

 multiplied by 100 to obtain the average number of 

 bacteria per cubic centimeter. 



Fig. 42. — Culture of 1-100 c.c. milk from separator which 

 had been flushed with warm water only. 



Measure from .1 to 1 c.c. of milk into test tubes 

 containing 5 c.c.'s sterile water (water blanks). To 

 a given number of these add 5 c.c. of washing powder 

 in solution. Pour contents of each tube into test 

 tubes containing melted agar. Shake thoroughly 



