296 MILK 



to personal hygiene of operators. There may be carriers of dis- 

 ease germs among the milkers, and in that case a real menace 

 is added to the milk. Perhaps the communication of patho- 

 genic bacteria from milkers who are carriers, or who are in the 

 incubation period of a communicable disease, or who are actu- 

 ally suffering from Ught attacks, as walking typhoid fever, for 

 example, cannot be entirely avoided by cleanly habits, but the 

 menace from a cleanly person is surely not as great as from a 

 careless one. Periodic medical examination of dairy employees is 

 desirable if communication of infectious diseases is to be avoided, 

 and even then the result is not absolutely certain. 



The method of milking has its influence on the germ content 

 of milk. The method commonly known as "wet milking" is car- 

 ried out by closing the thumb and forefinger around the upper end 

 of the teat and then gliding down to the aperture. The air is 

 squeezed out of the teat duct and suction created so that the milk 

 flows from the udder. 



The gliding causes considerable friction on the skin of the 

 teat and on the fingers of the milker. To remedy this trouble it 

 is customary to lubricate the hands. This is done by moistening 

 with some of the first milk or by the use of vaselin. Even saliva 

 has been used as a lubricant, but this filthy and dangerous habit 

 is becoming obsolete. 



When the hands are moistened with milk the dirt from the 

 teat is rapidly loosened and mixed with the milk. This naturally 

 increases the germ content. When the teats are smeared with 

 vaselin the number of germs removed during milking operations 

 is probably not great. Vaselin holds the dirt and with it the 

 micro-organisms on the skin so that they are not easily detached. 

 The use of vaselin or some other grease has been advocated by 

 some as a protection of the teat against undue friction, thereby 

 avoiding local inflammatory conditions. 



A more sanitary method of milking is becoming more popular, 

 although it requires more strength on the part of the milker and 

 consequently more practice and perseverance. This method of 

 "dry milking" is the only one permitted in the best dairies. The 

 thumb and forefinger are closed around the upper end of the 

 teat, and then, instead of gliding down, the other fingers are closed 

 on the teat in succession. The vacuum is created in this manner. 

 No lubricant is required in this method and the disadvantages of 

 wet milking are largely avoided. 



Still it does not seem that the average germ content of milk is 

 greatly increased by wet milking. Backhaus, for example, found 

 7833 to 9000 bacteria after wet milking and 5600 to 7400 after 

 dry milking. The difference between these numbers is not great, 



