390 CITY MILK SUPPLY 



results into groups as recommended by the American Public Health Association, 

 while a step in the right direction, is cumbersome and does not clearly indicate 

 whether or not a milk conforms to a given bacterial standard. 



The commission passed a resolution at its last meeting regarding the number 

 of bacterial tests necessary to determine the grade into which a milk falls, as 

 follows : 



That the grade into which a milk falls shall be determined bacteriologically by at 

 least five consecutive bacteria counts taken over a period of not less than one week nor 

 more than one month, and at least 80 per cent, (four out of five) must fall below the 

 limit set for the grade for which the classification is desired. 



On the subject of laboratory examinations of milk for bacteria the commis- 

 sion passed the following resolutions : 



1. That the interests of public health demand that the control of milk supplies, 

 both as to production and distribution, shall include regular laboratory examinations 

 of milk by bacteriological methods. 



2. That among present available routine laboratory methods for determining the 

 sanitary quality of milk the bacteria count occupies first place. 



3. That bacteriological standards should be a factor in classifying or grading milks 

 of different degrees of excellence. 



4. That in determining the grade or class of a raw milk the specimen taken for 

 bacteriological examination should be of milk as offered for sale. 



5. That there should be bacteriological standards for pasteurized milk which 

 should require laboratory examination of samples immediately before pasteurization 

 as well as of milk offered for sale. 



6. That the bacteria count of milk indicates its quality and history as it is modified 

 by contamination, handling, dirt, temperature, or age. A high count indicates the 

 necessity of investigation and inspection. 



7. That there be adopted as standards for making the bacteria count the standard 

 methods of the American Public Health Association, laboratory section, recommend- 

 ing, however, the following amendments : 



A. That the culture medium used for testing milk be identical in its composition 

 and reaction with the culture medium used for the testing of water provided in the 

 standard methods of water analyses of the American Public Health Association. 



B. That incubation of plate cultures be made at 37C. for 48 hr. 



The bacterial standards given in the report are the work of a special com- 

 mittee of bacteriologists who considered all of the bacterial standards now in use. 

 It is believed that the standards suggested are fair and wise and give full considera- 

 tion to the state of the industry and of public health control. The commission 

 believes that the adoption and enforcement of these bacterial standards will be 

 more effective than any other one thing in improving the sanitary character of 

 public milk supplies. The enforcement of these standards can be carried out 

 only by the regular and frequent laboratory examinations of milks for the num- 

 bers of bacteria they may contain. 



CHEMICAL STANDARDS 



The chemical standards suggested are the work of a special committee, com- 

 posed of chemists, which has carefully considered the natural composition of 

 milk and the Federal and State standards already established. The standard of 

 3.25 per cent, fat and 8.5 per cent, solids, not fat, here proposed is in accordance 



