MICRO-ORGANISMS IN MILK 327 



The bottles in which milk is sold require special care to avoid 

 undue pollution. Here also the number of bacteria may be 

 increased, and there is the further menace of communicable dis- 

 eases being carried in bottles. Milk is frequently delivered at 

 houses early in the morning and is left outside without ice, ex- 

 posed to the rays of the sun, and sometimes a prey to animals. 



Fig. 159. Sanitary hygienic milking stool. 



Domestic animals have been known to be carriers of diphtjieria 

 and other infectious diseases and may communicate the germs 

 of these diseases to the milk by licking the caps of exposed bottles. 

 Even after bottles have been cleaned and sterilized at the dairy 

 there is possible danger of reinfection by handling (Figs. 153-158). 



Fig. 160. Sanitary milking stool. 



As a matter of fact, the germ content of milk in bottles is usually 

 higher than in the milk as it leaves the cooler, whether the milk is 

 pasteurized or not (Figs. 159, 160). 



CONTAMINATION DURING TRANSPORTATION 



During transportation several causes may operate to increase 

 the germ content of milk. The most important factor is probably 



