GERMS IN RELATION TO MILK 37 



the fatality less in milk-borne epidemics. It is usually not possible to 

 :find the germ of the disease in the infected milk.* This follows be- 

 cause it often happens the milk was contaminated but for a short 

 time, perhaps but one day. Sometimes the milk is daily contamin- 

 ated for a considerable period, but the germs may be greatly diluted 

 in the milk or may be killed by the growth of lactic acid bacteria. 

 In only one instance out of 179 milk-borne epidemics of typhoid 

 fever was the typhoid germ found in the milk; and in but 2 out of 

 -23 epidemics of milk-borne diphtheria, was the diphtheria germ 

 •discovered in the milk. If the source of the contaminated milk is 

 found and its use stopped the epidemic will probably soon cease. 



Disease germs grow best in pasteurized milk, since they are 

 riot killed by the germ-destroying substance in fresh, raw milk, 

 nor by the acid produced by lactic acid bacteria. Readers who are 

 particularly interested in milk-borne outbreaks of contagious disease 

 are referred to Bull. No. 41, Hygienic Laboratory of the U. S. 

 Public Health and Marine-Hospital Service. 



The lesson which should be taken to heart is that no sick per- 

 son or one coming in contact with persons sick with communicable 

 •diseases, should be allowed to have anything to do with the hand- 

 ling of milk, milk utensils or be permitted entrance to barn or 

 dairy. Milk should be kept in a room separate from human hab- 

 itation, and all the utensils should be kept and cared for in this 

 milk room. Young children should be excluded from barn and 

 dairy, as they are much more prone to contagious diseases than 

 adults. Dogs and cats may be carriers of germs, dirt and parasites, 

 and should also be kept out of these places. The water used in 

 ■connection with the dairy should be examined for purity by a com- 

 petent chemist. (See p. 75.) 



* And it is not worth attempting unless from the original sample containing 

 the infecting organism. Tubercle bacilli in milk are found most certainly by 

 intraperitoneal injection of a guinea pig with the centrifuged sediment of 40 c. c. 

 <of milk in 2 c. c. of the same milk. 



