UNITED STATES DEPARTMENT OF AGRICULTURE 



^B BULLETIN No. 1114 ^» 



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Washington, D. C. 



PROFESSIONAL PAPER 



August 30, 1922 



THE DETECTION OF HYPOCHLORITES AND 

 CHLORAMINS IN MILK AND CREAM. 



By Fhilip Rt-pp, Dairy Chemist, Dalnj DiiisUm, Bureau of Animal Industry. 



CONTEXTS. 



Page. 



Outline of experimental work- 

 Preparation of reagents 



The test 



Reaction in milk 



Reaction in pasteurized milk- 

 Reaction in cream 



Summary 



Page. 

 4 

 4 



The use of hypochlorites and chloramins in the treatment of dairy 

 utensils has led to much speculation as to whether or not attempts 

 might be made to add these preparations to milk. This speculation 

 is due to the fact that there have been no methods for detecting small 

 amounts of chlorin in milk. The term "' chlorin," as used in this 

 paper, refers to the available chlorin derived from hypochlorites and 

 chloramins. 



OUTLINE OF EXPERIMENTAL WORK. 



Very small quantities of chlorin in water solution can easily be 

 detected, either by means of the iodid-starch or the o-toluidin test. 

 However, when applied to milk containing small amounts of chlorin, 

 these tests are of no value, because the chlorin has combined with 

 the protein of the milk and is not liberated readily at room tempera- 

 ture by the addition of acids. 



It seemed desirable, therefore, to devise some methods for the 

 demonstration of small amounts of hypochlorites or chloramins in 

 milk and cream. The question first arose, how firmly is the chlorin 

 united with the protein? If loosely combined, there was no reason 

 why it should not be liberated under proper conditions. 



On experiment it was found that the chlorin could be liberated; 

 and if liberated in the jiresence of potassium iodid, the chlorin 

 would displace the ioclin of the iodid, which would then combine 



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