32 Agricultural Bacteriology. 



especial harm results. In the whey, especially in that 

 from unclean tanks, are found injurious forms of bac- 

 teria that find their way from the whey to the cheese- 

 vat through the medium of the contaminated and poorly 

 washed milk can. In order to avoid this source of loss 

 a separate set of cans should be used in which to return 

 the by-products to the farm. At some cheese factories 

 and creameries the by-products are heated to the scald- 

 ing point before being returned to the farm. When so 

 handled the results are essentially as good as if a sepa- 

 rate set of cans were used. 



Washing milk utensils. All milk utensils should be 

 washed as soon as possible after using, for if the milk 

 is allowed to dry on the surface of such containers it 

 is very difficult to remove. They should be rinsed with 

 cool or hike-warm water, then thoroughly washed with 

 a hot solution of a washing powder, as Wyandotte or a 

 similar preparation, using, preferably, a stiff brush for 

 scrubbing. The use of soap and soap powders is to be 

 avoided for they are difficult to remove by rinsing and 

 are not as effective in the removal of the milk and 

 grease. The utensils should be well rinsed in boiling 

 water, using a large quantity, so that they will be thor- 

 oughly scalded. If the scalding is done with a small 

 amount of hot but not boiling water, the bacteria on the 

 walls of the utensils will not be destroyed. After 

 scalding they should be drained but never wiped. If 

 sufficient hot water is used, the utensil will be heated 

 so that it will dry quickly with no further attention. 

 The clean utensils should be stored in a place free from 

 dust. 



Wherever steam is available, the cleansing can be- 

 made much more effective by steaming, after rinsing 



