

264 BACTERIOLOGICAL ANALYSIS OF MILK. 



ent upon three factors: (i) The care in the dairy, (2) the 

 care in transportation, and (3) the temperature of the milk. 

 Milk produced in a filthy barn will contain larger numbers 

 of bacteria than milk produced in a clean barn, and milk 

 which has been subjected to improper conditions in trans- 

 portation will, in general, show more bacteria than milk 

 that has been properly handled. Hence it follows that the 

 quantitative analysis of milk will enable us to determine 

 approximately the cleanliness of the conditions under which 

 the milk has been produced and transported. If a sample 

 of milk is only a few hours old, and the number of bacteria 

 is large, it indicates that the conditions of its production have 

 been uncleanly. If, however, the sample of milk is older 

 and the number of bacteria is large, it indicates either that 

 the original conditions are uncleanly or that the milk has 

 not been properly treated subsequent to the milking. In 

 other words, if the number of bacteria in a sample of market 

 milk is found to be excessive, the inference is drawn that the 

 milk is either very old, or has been kept too warm, or was 

 produced under conditions of filth and uncleanliness. On 

 the other hand, if the number of bacteria is found to be small 

 it would indicate (leaving out of account the possibility of 

 the presence of antiseptics) that the conditions of produc- 

 tion and transportation have been satisfactory. While the 

 presence of a large or a small number will not positively de- 

 termine the wholesomeness of the milk, the quantitative de- 

 termination will give us a means of drawing a conclusion as 

 to the conditions under which the milk has been produced. 



While it is true that milk containing small numbers of 

 bacteria may contain some pathogenic forms and thus 

 be dangerous, nevertheless milk produced under proper 

 dairy conditions is far less liable to be contaminated with 

 pathogenic germs than milk that is carelessly handled. The 

 dairyman who has taken special care to protect his milk from 

 bacteria will be more likely to have taken care to protect it 



