232 MILK HYGIENE 



so doing, an opinion can be formed as to the genuine- 

 ness of the claims of the milk companies, as well as the 

 cleanliness and care with which the milk has been han- 

 dled from the time it was drawn until it was sold. There 

 are special reasons for making regular bacteriological 

 examinations of nursery milk; it must be required not 

 only that this shall come from healthy animals and not 

 be exposed to infection with pathogenic bacteria, but, 

 at the same time, it is well to require that it shall not 

 contain an excess of bacteria at the time it is delivered 

 to customers. In this connection, it would be very ad- 

 vantageous to make a stipulation to the effect that ves- 

 sels [bottles] in which infants' milk is sold shall be pro- 

 vided with a label giving the day on which the milk was 

 produced. A bacteriological examination of infants' 

 milk is of importance as indicating the thoroughness and 

 effectiveness of the methods of the concern and as indi- 

 cating the need, perhaps, of subjecting these methods to 

 tliorough revision. 



There are other reasons for establishing a bacterio- 

 logical examination of pasteurized (and sterilized) milk, 

 since, in this way, most important information may be 

 gained concerning the reliability or the inefficiency of 

 the methods in use by the various concerns. It would 

 also be of advantage, in connection with this inspection, 

 to require that the containers of pasteurized milk shall 

 be marked with a tag showing the day and method of 

 pasteurization (or sterilization). 



The counting of bacteria in milk is not a difficult 

 matter, but when many samples are to be examined in 

 this way much time is required. The method is, in gen- 

 eral, the same as that used for estimating the number 

 of bacteria in water or other fluids ( see the text-books on 

 bacteriology). It is best to use gelatin that has been 

 made with milk. A good way is to add 100 grms. of gel a- 



