DAIRY INSPECTION 191 



effect it also usually exposes the apparatus to contami- 

 nation with germ-laden dust. 



When facilities for sterilization by steam are not 

 available, the milk vessels and utensils may be sterilized 

 by submerging them for 20 minutes in a 0.1 per cent, 

 solution of hypochlorous acid after they have been 

 cleansed in the usual way. Hypochlorous acid is even 

 more effective as a germicide than the hypochlorites, al- 

 though the latter are 150 to 200 times as powerful as 

 carbolic acid. A 0.1 per cent, solution will kill typhoid 

 bacilli in 2% minutes. The solution may be conveni- 

 ently prepared as follows: Mix together equal parts by 

 weight of finely ground commercial bleaching powder 

 (chloride of lime) and powdered boric acid; keep in a 

 well-stoppered bottle and protect from light. Dissolve 

 6 drams of the powder in a quart of water by shaking 

 thoroughly, let stand for 24 hours and pour off the 

 clear fluid; then add 4 quarts of water. This makes a 

 solution containing 0.1 per cent, of hypochlorous acid. 

 When milk bottles are submerged in this solution for 

 20 minutes, drained for 10 to 20 minutes, and then filled 

 with milk and capped, no odor or taste of chlorine can 

 be detected in the milk. Milk can be strained through 

 cheese cloth moistened with the solution without any 

 effect upon the odor or taste. Tin vessels are not cor- 

 roded. The powder from which the solution is pre- 

 pared may be kept for some time under proper condi- 

 tions, but the solution rapidly loses strength and be- 

 comes ineffective in three weeks. Calcium hypochlo- 

 rite has been in use for a long time as a disinfectant for 

 water supplies and a solution containing 1 ounce to 125 

 gallons of water is recommended for the sterilization of 

 milk vessels and utensils, but it is much more expensive 



