PRESERVING FOOD 
67 
ing qualities of milk or cream. As it is not a process 
of sterilization, such milk, sometimes grows putrid or 
bitter without souring. 
FIG. 39. Diagram Showing Effect of Pasteurization Upon Milk. 
Fig. 39 represents the change which takes place in 
the germ content of milk during this process. If we 
represent the germ content of a sample of raw milk 
by the size of the white square, then the black square 
will show the same after Pasteurization. 
All additions of bacterial poisons are liable to injure 
