FERMENTED MILKS 23 
by a steam hose. If a larger quantity is made, one of the starter 
cans used in creameries will be found convenient. These are essen- 
tially cylindrical vats with mechanical stirrers and a jacket which can 
be filled with steam for heating or water for cooling. The milk 
should be held at a temperature of at least 180° F. for not less than 
30 minutes. 
The milk is cooled to about 100° F. One-half of the milk is 
drawn off and inoculated with a culture of the sour-milk organism. 
The remaining half is inoculated with the bulgaricus culture ob- 
tained from daily propagation. The amount to be added will de- 
pend upon the quantity of milk to be fermented, the time at which 
it is desired to have it curdled, and the temperature maintained 
during the fermentation. This can best be determined by experience. 
On pint should be sufficient for any amount between 10 and 20 
gallons. 
The milk inoculated with the sour-milk organism may be held at 
ordinary room temperature. Precautions must be taken to hold 
that part inoculated with the bulgaricus culture at a temperature of 
90° to 100° F. for several hours. If the milk is in cans it ma}^ be 
set in a tub of warm water. A large volume of milk in a warm 
room will maintain the proper temperature. 
If it is impossible to hold the milk at the desired temperature, the 
amount of culture inoculation should be increased. 
When the milk has curdled, which should be in 10 or 12 hours, the 
two lots should be poured together and thoroughly mixed by churn- 
ing or stirring. It may then be bottled and put on ice to check the 
acid formation. 
BIBLIOGRAPHY 
The following bibliography, although not exhaustive, contains 
the most important papers on fermented milks and will be useful 
to those who care to take up this question in more detail. 
(1) Albus, W. R., and Holm, G. E. 
1926. THE EFFECT OF SURFACE TENSION UPON THE GROWTH OF LACTOBACIL- 
LUS ACIDOPHILUS AND LACTOBACILLUS BULGARICUS. J0U1\ Bact. 
12: 13-1S, illus. 
(2) Arnold, L. R. 
1899. contribution a l'etude des laits fermentes. le leben. 41 p. 
Montpellier. (These.) [Abstract in Jahresber. Galirungs- 
Organ. (1899) 10: 22G. 1901.] 
(3) Bass, C. C. 
1924. PRODUCTION OF ACIDOPHILUS MILK ON A LARGE SCALE FOR GENERAL 
use. Jour. Airier. Med. Assoc. 82: 1503-1504. 
(4) Belonovsky, J. 
1907. influence du ferment lacttque SUR LA FLORE des excrements 
des souris. Ann. Inst. Pasteur 21: [991]-1004. 
(5) Bertrand, G., and Duchacek, F. 
1909. action du ferment bulgare sur les principaux sucres. Ann. 
Inst. Pasteur 23: [4021^14. 
(6) ■ and Weiswehler, G. 
1906. action du ferment bulgare sur le lait. Ann. Inst. Pasteur 20 : 
[977] -990. 
(7) Beyerinck, M. W. 
1889. sur le kefir. Arch. Neerland. Sci. Exact, et Nat. 2S : [42S]- 
444, illus. 
