THE ALCOHOL TEST IN RELATION TO MILK. 
17 
Table 13. — Effect of heat on the alcohol test with milk in which the positive lest is due to 
rennet action. 
Milk heated 
to— 
Alcohol test. 
75 per cent. 
68 per cent. 
Experi- 
ment I. 
Experi- 
ment II. 
Experi- 
ment I. 
Experi- 
ment II. 
°C. 
Not heated... 
40 
i+L 
+ L 
+ L 
+ L 
+s 
+ L 
+ L 
+L 
+L 
+VS 
+ L 
+ L 
+ L 
+ L 
+s 
+ L 
+ L 
+ L 
+L 
+VS 
60 
70 
80 
90 
Note.— Acidity of milk in experiment I, 1.82; in experiment II, 1.84. 
1 See footnote under Table 1. 
The results which we have shown on the effect of rennet action in 
relation to the alcohol test confirm the work of other investigators, 
and it is evident that the rennet-forming group of bacteria in milk 
can play an important part in the production of a positive alcohol test. 
INFLUENCE ON THE ALCOHOL TEST OF CARBON DIOXID IN MILK. 
There are probably numerous minor ' factors which influence the 
alcohol test with market milk. While the two principal factors are 
probably acidity and the effect of rennet action, it is believed by some 
investigators that carbon dioxid plays a more or less important part. 
Auzinger (2) found that milk one hour old which gave a positive 
alcohol test gave a negative test after it had been held for 18 hours. 
He believes that carbon dioxid might be partly responsible for such a 
change. 
We have passed carbon-dioxid gas into milk many times and have 
always been able to cause a positive alcohol test. In one experiment 
carbon-dioxid gas was passed into milk until the acidity was 2.36 
(titration in cold milk with phenolphthalein as an indicator), and a 
positive alcohol test was obtained with 75 per cent and 68 per cent 
alcohol. As is shown in Table 14, this milk was heated at different 
temperatures up to 100° C. With the increase in temperature the 
acidity was reduced, due probably to the expelling of the C0 2 . Barille 
(4) has shown that carbon dioxid forms a very unstable compound, 
which he calls carbono phosphate of calcium and is easily broken up 
by heat. When the temperature reached 70° C, the alcohol test with 
68 per cent alcohol was negative and the acidity had been reduced 
from 2.36 to 2.05. At 90° C. the acidity was 1.91 and the alcohol 
test was negative with 75 per cent alcohol. 
There can be no doubt as to the fact that carbon dioxid may cause 
a positive alcohol test, provided there is a large enough amount in the 
82832°— Bull. 202—15 3 
