Part II.] MILK INSPECTION. 81 



through proper pasteurization. Proper pasteurization, coupled 

 with medical supervision of the milk plant men, is coming to be 

 recognized as a further step in advance. When the public milk 

 .supply has been properly pasteurized and delivered with reason- 

 able promptness, it is to be fairly considered as one, of the very 

 safest of our human foods. The dairy inspector who is de- 

 voting his efforts to a careful supervision of milk pasteurization 

 is in a way to accomplish more in safeguarding the healthful- 

 ness of the milk supply than can be accomplished at present by 

 the same amount of effort expended in any other way. 



Cleanliness. — Fortunately little more needs to be said at 

 this point. The sediment test is simple and well understood. 

 When in the occasional instance this test shows an undue 

 amount of foreign matter in milk, the presentation of the 

 results to the responsible party practically always results in im- 

 provement. When such improvement does not result, addi- 

 tional means of procedure are at hand. Milk as it is now 

 ordinarily produced and delivered is one of our cleanest foods. 



Keeping Quality. — Milk may be rich in fat, carefully pas- 

 teurized and thoroughly clean, but if it is sour when delivered 

 it will be considered by the consumer to be bad milk. At 

 present the most commonly considered test of keeping quality 

 is the bacterial count. Milk will rarely sour until its germ con- 

 tent amounts to some millions per cubic centimeter. On the 

 other hand, making the bacterial count is a highly technical 

 process, requiring fairly extensive laboratory equipment and the 

 lapse of considerable time. The count as obtained is subject to 

 considerable variation, and the point at which either the sour 

 taste is noticeable or the milk is curdled does not coincide with 

 any definite number of germs per cubic centimeter. The mi- 

 croscopic method of counting bacteria has some advantages 

 over the plate method, but the microscopic method is not 

 readily applicable where the germ content is relatively low. 



The earlier and simpler method of estimating the probable 

 keeping quality was by titration of the acid produced by the 

 germ life. Like the microscopic count of the bacteria, this 

 titration method is most applicable to milk of doubtful quality. 



In Europe much attention has been given the reductase test. 

 Like the microscopic method and the titration of acid, this test 



