CONTROL OF THE PUBLIC MILK SUPPLY 447 



often hard to get convictions because it is difficult to present the subject 

 of bacterial contamination of milk to jurors in an intelligible way. They 

 understand the significance of skimming, watering and of the addition 

 of preservatives but bacteria are rather beyond them and they are in- 

 clined to think that in selling milk of a prescribed bacterial count the 

 milk dealer has been guilty of violating a technical provision of the code 

 of little importance and accordingly to deal leniently with him. More- 

 over, cases brought against dealers for violation of the bacterial standard 

 are apt to be expensive to try for they offer plenty of opportunity for 

 the introduction of expert testimony. Besides, although decisions have 

 been rendered that uphold bacterial standards some health officials doubt 

 whether the highest courts would sustain them and are loth to make the 

 test. The net result is that, although many cities have bacterial 

 standards, the number of cases that are brought for violating them are 

 few, although milk that contains bacteria in excess of the standards is 

 often sold. One reason for this, apart from any question as to the legality 

 or illegality of the standard, is that it is considered better policy to call 

 the attention of dealers to the fact that their milk violates the standard, 

 in the hope that they will find the cause and bring down the count, than 

 it is to prosecute freely. 



The question may then be asked, of what value are bacterial stand- 

 ards? They are useful in that the public sooner or later begins to demand 

 milk that complies with the standards and then the dealers begin to 

 furnish it. To do this they have to improve in their methods of doing 

 business and it results that boards of health and other agencies take 

 part in educating dairymen, contractors and consumers as to how milk 

 should be produced and cared for, with the result that better milk is 

 marketed. 



Significance of Predominance of Acid-forming and of Putrefactive 

 Bacteria. The better laboratories supplement the bacterial count with 

 other tests that are designed to show the relative number of lactic, gas- 

 forming and putrefactive bacteria in the milk and from these determina- 

 tions make certain tentative conclusions. Milks showing a high percent- 

 age of lactic organisms suggest that the milk may have been produced 

 under cleanly conditions but that there has been time for these organisms 

 to grow, or that possibly the utensils are not kept clean and sterile. 

 Large numbers of gas-forming and putrefactive bacteria are indicative 

 of dirty methods. Similarly, other tests are used and deductions made 

 from them. Such tests often enable inspectors to economize time by 

 indicating the probable source of trouble that they are sent out to help 

 some farmer find and eliminate. 



Significance of the Streptococci. Besides using the bacterial count 

 in controlling the milk supply it has been proposed to use other bacterio- 

 logical tests as a basis for excluding milk from the market. 



