Contamination of Milk. 27 



the market, there is altogether too thin a veneer of solder 

 to effectually cover the joints. 



34. Use of milk-cans for transporting" factory by- 

 products. The general custom of using the milk-cans 

 to carry back to the farm the factory by-products (skim- 

 milk or whey) has much in it that is to be deprecated. 

 These by-products are generally rich in bacterial life, 



FIG. 6. The wrong and the right kind of a milk-pail. A, the ordinary type of 

 pail showing sharp angle between sides and bottom; B, the same properly 

 flushed with solder so as to facilitate thorough cleaning. The lower figure rep- 

 resents a joint as ordinarily made in tinware. The depression a affords a place 

 of refuge for bacteria from which they are not readily dislodged. This open joint 

 should be filled completely with solder. 



more especially where the closest scrutiny is not given to 

 the daily cleaning of the vats and tanks. Too frequently 

 the cans are not cleaned immediately upon arrival at the 

 farm, so that the conditions are favorable for rapid fer- 

 mentation. This danger can be entirely obviated by a 

 thorough cleansing process, but the patron who is shift- 

 less in regard to his cans will generally be lax in his 

 treatment of these vessels, and thus the opportunity for 

 infection is present. 



Many of the taints that bother factories are directly 

 traceable to such a cause. A few dirty patrons will thus 

 seriously infect the whole supply. 



