446 
Journal of Agricultural Research 
Vol. XI, No. 9 
IV. CATALASE CONTENT OF MILK AND BUTTER 
Storch's method of measuring the catalase of milk, as given by Barthel 
(6), gave very closely agreeing duplicate results and was used in this work 
(Table IX). In milk the liberation of oxygen ceased in four hours. The 
curd extracts were equal in volume to the original butter. Five per 
cent of commercial hydrogen peroxid was added to the samples to be 
tested, and the concentration of peroxid in the boiled samples at the 
end of four hours were used as the basis for calculation. 
Table IX. —Catalase content of milk and butter as shown by reaction with hydrogen 
peroxid 
Sample, 
Hydrogen peroxid con¬ 
tent after 4 hours. 
Reduction 
of hydro¬ 
gen peroxid 
in unboiled 
milk or 
butter. 
Boiled. 
Unboiled. 
i. Boiled milk. 
Gm. 
O. 0054 
Gm. 
Gm. 
Milk. 
O. 0039 
0. 0015 
a. Boiled fresh dairy butter. 
.0054 
Fresh dairy butter. 
. 0049 
. 0049 
. 0026 
.0039 
. 0048 
. 0005 
. 0005 
. 0028 
. 0015 
. 0006 
3. Stored dairy butter. .. 
4. Fresh centralized butter. 
5. Stored centralized butter. 
6. Fresh pasteurized creamery butter. 
The fresh centralized butter did not contain as much catalase as the 
results show, because a clear filtrate was not obtained. Every sample 
of butter contained catalase. That the centralized butter gave higher 
results than the other butter and as high as milk itself agrees with the 
belief that there is some relationship existing between catalase activity 
in milk and bacterial growth. Storage did not diminish its activity. 
V. PEROXIDASE CONTENT OF MILK AND BUTTER 
The common Storch test for heated milk was used on the butter 
extracts with the following results: 
Table X. —Color changes showing the peroxidase content of milk and butter 
Sample. 
Time of heating (in minutes). 
0 
5 
10 
20 
30 
1. Fresh dairy milk 
boiled. 
Fresh dairy milk. 
2. Stored dairy milk. 
3. Fresh centralized.... 
4. Stored centralized— 
5. Fresh pasteurized 
creamery. 
White... 
...do- 
...do.... 
...do.... 
White... 
Gray. .. 
White... 
Gray. .. 
White... 
...do.... 
White. 
Gray. 
White. 
Gray. 
Faint gray. 
White. 
White. 
Gray. 
Faint gray. 
Gray. 
Faint gray. 
White. 
Gray. 
Faint gray. 
Gray. 
Faint gray. 
Do. 
