26 CLEAN MILK 



produced from a herd of ioo grade Jersey and Guernseys which 

 has had a bacterial count below 1,000 for one year and an average 

 of 150 bacteria for 15 successive weeks from samples taken at ran- 

 dom in the city. 



The usual contamination of milk with germs may be judged 

 by the following figures with the understanding that great improve- 

 ment is taking place owing to the interest which has been shown 

 in the matter of obtaining a pure milk supply in recent years by 

 physicians and others. In Boston, during the spring of 1890, 57 

 samples of milk showed an average of 2,355,500 germs in the 

 better class milk, and of 4,557,000 germs in grocery milk. In winter 

 the growth of germs is considerably lessened by the colder temper- 

 ature and this is somewhat counterbalanced by the filthier condi- 

 tions of the barn floors, air and of the animals. On the whole, 

 winter milk is, however, much freer from germs. The New York 

 County Medical Society issue a certificate of inspection to farmers 

 who will follow their directions for producing a second-grade, pure 

 milk which shall not average over 100,000 germs from May to 

 October, and not over 60,000 germs from October to May. In 

 Seattle I found in twenty-eight examinations of different samples, 

 of milk on as many days in May and June, that sixteen samples 

 averaged over 3,000,000 germs, and twelve samples less than 1,000,- 

 000 germs per cubic centimeter. The examination of these milk 

 samples was done when the milk was fifteen to thirty-six hours old, 

 on the way to the consumer's house, being taken from the delivery 

 wagons or on arrival of the milk train. 



A great many conditions may alter the number of germs in 

 milk if milk is not produced and handled in a proper manner. Time 

 and temperature are the two most important factors upon which 

 the growth of germs depends — and the greatest of these is temper- 

 ature. The milk from one farm examined at the same hour on 

 two consecutive days averaged 1,150,000 germs on the first day — 

 which was warm for May — and 48,000 germs the following day, 



