THE ALCOHOL TEST IN EELATION TO MILK. 13 



Table 8. — Effect on the alcohol test produced by neutralizing the acidity of milk. 



Amount 





Alcohol test. 





Alcohol test. 



of normal 

 lactic 











Acidity 

















acid 



Acidity. 









after neu- 









added to 





75 per 



68 per 



44 per 



tralizing. 



75 per 



68 per 



44 per 



50 c. c. 





cent. 



cent. 



cent. 





cent. 



cent. 



cent. 



of milk. 



















e.c. 



















0.0 

 0.1 



1.84 

 2.08 



» +M 



+M 



— 











1.80 



_ 



_ 



_ 



0.3 



2.42 



+M 



+M 



— 



1.81 



— 



— 



— 



0.5 



2.99 



+L 



+M 



+VS 



1.64 



— 



— 



— 



0.8 



3.54 



+L 



+L 



+M 



1.60 



+VS 



— 



— 



1.0 



3.94 



+L 



+L 



+L 



1.60 



+s 



— 



— 



1.5 



4.30 



+L 



+L 



+L 



1.90 



+ L 



+ M 



— 



1 See footnote under Table 1. 



EFFECT OF HEAT COMBINED WITH ACIDITY. 



As a matter of general interest we may mention the effect of heat- 

 ing milk which gave a positive alcohol test. Auzinger (2) found 

 that a milk which gave a positive test at 15° C. sometimes did not 

 give the test when heated for 30 minutes at 60° C. Then again he 

 found that the test might remain positive in milk heated to boiling. 

 In Table 9 is shown the result of an experiment showing the effect 

 of heat on the alcohol test with milk of two different acidities. No 

 effect of heat was found on the sample of milk with an acidity of 

 2.30, but there was a marked effect when the acidity was lower. 



We have no explanation to offer for this negative result of the test 

 when the acidity is low. This action of heat might be of importance 

 when the alcohol test is applied to pasteurized milk. 



Table 9. — Effect of heat on the alcohol test which is positive on account of acid action. 



Milk heated 

 to— 



Alcohol test. 



Acidity, 2. 



Acidity, 2.30. 



75 per 

 cent. 



68 per 

 cent. 



75 per 

 cent. 



68 per 

 cent. 



"C. 

 Not heated... 

 40 



i+M 



+ M 

 + M 

 +M 

 + S 



+S 



+s 

 +s 



+VS 



+L 

 +L 

 +L 

 +L 

 +L 

 +L 

 +L 



+L 

 +L 

 +L 

 +L 

 +L 

 +L 

 +L 



60 



70 



80 



90 



100 





1 See footnote under Table 1. 



