35 



BULLETIN OF 

 MASSACHUSETTS BOARD OF AGRICULTURE. 



WHY MILK SOURS, AND HOW THE SOURING CAN BE 

 PREVENTED OR AT LEAST DELAYED. 



By Geo. M. Whitakek, A.M., 

 Acting Executive Officer of the Massachusetts Dairy Bureau. 



During the hot summer weather milkmen have much trouble with 

 sour milk and there is especial complaint of the large amount of 

 sour milk in Boston. In spite of the thousands of cans of surplus, 

 when the pinch of a warm spell comes, the surplus is wiped out by 

 the sour milk, and the contractors have hardly enough sweet milk 

 to supply their trade. The same is true, though to a less extent, 

 in other places. Now, this is unnecessary. So much is known 

 about the causes of milk souring that any farmer can avail himself 

 of this information and profit thereby. Sour milk is inexcusable 

 nowadays, and here is one of the things wherein modern science 

 has done much for dairying. The souring of milk is caused by 

 the presence in it of bacteria, the tiniest forms of organic life 

 known ; no bacteria, no sour milk. 



Milk in the udder of a healthy cow is free from bacteria, the 

 germs of decay coming chiefly from the air. If milk could be 

 drawn through a sterilized tube into an air-tight sterilized pail it 

 would remain unchanged for all time. Bacteria are numerous in 

 the air, and under ordinary conditions it is absolutely impossible 

 to have milk without any bacteria at all. We cannot expect to 

 prevent the entrance of all bacterial life into milk, but the number 

 may be greatly diminished by certain precautions. They are in- 

 timately associated with dirt and carelessness, and by the exercise 

 of scrupulous care and the observance of cleanliness we may keep 

 the number of bacteria down to the lowest possible limits. Then 



