444 CITY MILK SUPPLY 



These difficulties in bacteriological analysis are fully recognized and 

 competent analysts give them due consideration in interpreting results. 

 Consequently objections to the bacterial count based on these discrep- 

 ancies merely amount to the charge that the method is not refined enough 

 to warrant so much stress being put on its use. The validity of this 

 accusation, of course, depends on the way the analyses are interpreted 

 and to the uses they are put. There is no doubt but the attempt has 

 been made, particularly by untrained officials, to draw too fine distinc- 

 tions from bacteriological findings and it is equally certain those who 

 know how to use them find them sufficiently accurate to enable them to 

 classify the milks of the various dairymen with whom they are dealing 

 and to help correct the shortcomings of some of them. But objections 

 to the bacterial count are not limited to these inaccuracies; it is held by 

 some to be irrational, as applied to raw milk. 



Some Factors That Should be Considered in Using the Bacterial 

 Count. The point is made that it is the kind of bacteria, to wit, the dis- 

 ease germs and not the number present, that is important for it is not only 

 possible but even probable that in most instances in which milks show 

 high counts the microbes are perfectly innocuous forms such as the lactic 

 acid germs, whereas it is conceivable that a milk carrying but few bacteria 

 may be infected with disease germs. To this it is replied that in the case 

 of children there is evidence that their tender intestinal tracts may be 

 overwhelmed by mere numbers of microorganisms and also that large 

 numbers of bacteria in milk indicate that it has been produced under 

 filthy conditions or has been mishandled. 



When milk is sampled on the farm and plated shortly thereafter, the 

 bacterial count is within limits a measure of the amount of contamination 

 the milk is receiving for the germs are largely those that are introduced 

 from fecal matter, the hands of the milker, the feed, the utensils, etc., 

 but as time lapses this is no longer true for then the bacterial count is the 

 result not of a single factor but of three, namely, of dirty dairying, of 

 high temperature and of age. It is pointed out that in winter, or in 

 summer as a result of liberal icing, the milk of a dirty dairyman may 

 compare favorably, so far as the bacterial count is concerned, with milk 

 produced by dairymen who are scrupulously clean. Also, it is contended 

 that the count so far as it is indicative of dirt, does not distinguish be- 

 tween human dirt, which is most likely to be harmful, and animal dirt, 

 which is comparatively harmless. In reply to these allegations it is 

 admitted that cold for a longer or shorter time may keep down the bac- 

 terial counts of an unclean dairy to the average of those of clean ones but 

 it is maintained that fluctuations in the count of the milk of the dirty 

 dairy, owing to failure to always maintain low temperatures, are bound to 

 occur with sufficient frequency to direct suspicion to the milk and ulti- 

 mately to condemn it. Furthermore, it is maintained that while it is 



