BULLETIN 1114, U. S. DEPARTMEXT OF AGRICULTURE. 

 Table 1. — The hitpochlonte test In tabular form} 



Test. 



Parts of available chlorin with different color reactions. 



1:1,000 



1:2,500 



1 : 5,000 



1 : 10,000 



1 : 25,000 



1 : 50,000 



Tfike ."i c.r.. millr 



Reddish 



color. 

 Yellowish 



brown. 

 Yellowish 



brown. 

 Yellowish 



brown. 



Blue purple . 



Slightly 



discolored. 



Deep yellow. 



Deep yellow. 



Deep yellow. 



Blue purple, 



■ 











Add 1.5 c.c. iodid solu- 



Pale yellow, 



fades. 

 Light yellow 



Yellow 



Blue purple. 









tion. Milk appears. 

 Add 4 c.c. HCl. Curd 









appears. 



After heating at 85° C. 

 and cooling, the curd 

 and liquid below ap- 

 pear. 



Add 0.5 c.c. starch solu- 

 tion. Liquid below 

 curd appears. 



YeUow... 



Dark - red 



purple. 



Pale yellow. 

 Red purple. 



YeUowish. 



Pale-red 

 purple. 



1 The test for chloramins is approximately the same. 



REACTION IN PASTEURIZED MILK. 



If hypochlorite sohition is added to milk in different proportions 

 and the milk is then pasteurized at 145° F, for 30 minutes, the 

 results obtained by the above test after the milk has been kept in 

 the ice box for 24 hours are approximately the same as with raw 

 milk. 



REACTION IN CREAM. 



Hypochlorites' or chloramins added to 20 per cent cream in dif- 

 ferent proportions give results approximately the same as with 

 milk. 



With 1 part of chlorin in 2,500 parts of cream, the cream turns 

 yellow on adding the iodid solution. At 1 : 5,000 dilution and 

 above, no change is apparent after adding hydrochloric acid to the 

 cream-iodid mixture, and it is necessary to heat the cream in order 

 to bring about the reaction. At 1 : 25,000 dilution both the curd 

 and the liquid below are a pale yellow, while at 1 : 50,000 dilution 

 the curd is a little more yellow than the control and the liquid below 

 is the same as in the control. After adding starch to the liquid 

 below the curd, it acquires a pale-red purple color with hypo- 

 chlorites at 1 : 50.000 dilution, while with chloramins it remains 

 the same as the control at this dilution. At 1 : 25,000 dilution the 

 reaction is distinct with chloramins. 



After heating the cream-iodid-hydrochloric-acid mixture, the pres- 

 ence of small amounts of chlorin must be judged by the color of 

 the liquid below the curd, because the curd, owing to the presence of 

 the fat globules, has a pale-yellowish color. The yellow color of the 

 curd becomes more marked as the amount of chlorin present in- 

 creases, while the liquid below the curd has the same color as in milk. 



The above test applies equally well after the milk or cream has 

 been kept in the ice box for 48 hours. 



