REPORT OF CHEMICAL DEPARTMENT. 
meee PP RCT OF vPREATING: MILK: WITH 
CARBON DIOXIDE GAS UNDER 
PRESSURE? 
L.L. VAN SLYKE anp ALFRED W. BOSWORTH. 
SUMMARY. 
I. In making a study of the chemical changes in kumiss made 
from cows’ milk, it was noticed that lactic acid forms in it much 
more slowly than in ordinary milk. This was found to be due to 
the action of carbon dioxide gas under pressure. 
2. A series of experiments was undertaken in order to ascertain 
the effect of carbon dioxide under different pressures upon the 
development of lactic acid in milk, 
3. The milk used was (1) fresh, separator skim-milk, (2) fresh 
whole milk, drawn and handled under good hygienic conditions, 
(3) fresh skim-milk pasteurized at 185° F. and (4) fresh whole 
milk pasteurized at 185° F. 
4. The pressures of gas employed were 70, 150 and 175 pounds 
per square inch. 
5. lhe most effective method of treating the milk was to charge 
it with carbon dioxide gas at the desired pressure in a tank such 
as is used in bottling establishments in preparing carbonated drinks 
and then to fill into bottles. 
6. The carbonated milk was kept at temperatures varying from 
258:16.70° F. 
7, Pasteurized milk, carbonated, kept for five months with little 
increase: of acidity. Fresh, whole milk, carbonated, kept, in one 
experiment, for about the same length of time. 
8. Carbonated milk makes a pleasant beverage and may find prac- 
tical use as a healthful drink. It may also be found useful for tn- 
valids and children. 
*A reprint of Bulletin No. 292. 
