12 CLEAN MILK 



public use of pasteurized milk* there arises the difficulty of determin- 

 ing its true condition by ordinary tests at our command. Thus it 

 may not show acidity when old (as lactic acid germs are most 

 readily killed by heat), nor may it be altered in appearance or taste, 

 and yet be swarming with deleterious germs — if kept for some time 

 at low temperature. 



These last remarks apply particularly to pasteurized' milk which 

 has been insufficiently heated (not uncommonly so in commerce as 

 regards time of heating), or which has been placed in dirty or un- 

 sealed containers, or to that which has not been rapidly cooled, or 

 to that which was too dirty and germ-laden before heating, or to 

 milk kept too long after heating. Therefore it will be seen that 

 pasteurization will not make a dirty or old milk harmless, and 

 that the same care in cooling, in the use of clean utensils, in 

 avoidance of contamination in handling, together with the necessity 

 for its speedy consumption, are as essential as with clean, unheated 

 milk. 



Against all objections to pasteurized milk the one salient, un- 

 deniable fact stands out, viz., that properly pasteurized milk is a 

 comparatively safe food, whereas unheated milk is not. This fol- 

 lows because occasionally in the most carefully handled certified 

 milk contamination with contagious disease may occur, while in 

 ordinary market milk not only is this clanger present, but that of 

 tuberculosis germs, and the many miscellaneous bacteria arising 

 from manure, filth, impure water and utensils and disease of cows. 

 But since the chance of harm from certified milk is slight, and be- 

 cause of objections noted regarding pasteurized milk generally, 

 Melvin has offered the following solution. He advises that 

 all market milk, except such as is " certified " or " inspected," be 

 subjected to compulsory pasteurization under the supervision and 

 control of health authorities (see p. 186) 



* For municipal regulations of pasteurized milk see p. 216. 



