328 



CITY MILK SUPPLY 



Bottle Washing. Bottles are washed by hand in the small dairies 

 and by machines in the larger ones. In hand washing the bottle is merely 

 swabbed out with a brush and the bottles rinsed in a tank; in somewhat 

 larger dairies the bottles are washed by revolving, power-driven brushes 

 and rinsed in a tank or quite as often, over small jet machines. The 

 largest dairies use big automatic bottle washers that wash the bottles 

 in their cases. The machines are made by several manufacturers and 

 of course, differ from one another in construction but in general they have 

 a soaking tank or compartment, a washing compartment where the bottles 

 are cleaned by revolving brushes or more often by jets of hot water shot 

 into the bottle and case under high pressure, a rinsing compartment where 

 jets of hotter water play on the bottles and finally a sterilizing compartment 

 where the bottles are put into boiling water, or have either jets of very 

 hot water or of steam played on them. These machines wash all but the 

 exceedingly dirty "alley" bottles clean, and are no doubt capable of 

 killing all of the non-spore-bearing germs if run at the temperature directed 

 by their makers but if dairymen economize by cutting down the heat, 

 these washers do not sterilize the bottles. Inspectors should satisfy 

 themselves that the machines are operated properly. A cold washroom 

 full of vapor is no guarantee that the sterilization that is being attempted 

 by steam is effective. 



Cost of Bottle Washing. The Dairy Division of the U. S. Department 

 of Agriculture has made a study of the cost of washing bottles. Data 



TABLE 93. COST OP WASHING MILK BOTTLES IN 91 PLANTS BY AUTOMATIC, BY 

 BRUSH MACHINES AND BY HAND (U. S. DEPARTMENT OF AGRICULTURE) 



TABLE 94. COMPARISON OP THE COST OF WASHING BOTTLES IN FIVE CITIES OF THE 

 UNITED STATES (U. S. DEPARTMENT OF AGRICULTURE) 



