Nov. 24, 1923 
Active Chlorin as a Germicide for Milk 
379 
The most notable fact about using chlorin in this form is that no flavor 
is imparted to the milk in even the strongest dilution used in this test, 
114000. A dilution of 113000 gave a very slight flavor, but one that 
would not be detected after a short time. Compared to this, a dilution 
of 1:10000 of sodium hypochlorite gave a decided flavor. 
Tests for the purpose of comparing the germicidal action of active 
chlorin from various sources upon certain specific organisms were then 
made. In the first, milk was inoculated with Staphylococcus pyogenes 
aureus at 4.30 p. m., heated on the water bath to 37 0 C., and then allowed 
to stand at room temperature until 10 a. m. the next day. This organism 
was used as the colonies could be easily identified, as it is at times found 
in milk and is pathogenic. The results are given in Table VII. 
Table VII. —Action of chlorin water and calcium hypochlorite on Staphylococcus 
pyogenes aureus 
Number of bacteria with— 
Active chlorin. 
Time acting. 
Chlorin water. 
Calcium hypochlorite. 
1:3000. 
1:5000. 
1:7000. 
I:1OOOO 
i:15000 
1:20000 
4 hours. 
... .do. 
... .do. 
... .do. 
_do. 
... .do. 
Little decrease . .. 
Decided decrease. 
_do. 
Practically sterile 
Decided decrease. 
_do. 
Practically no decrease. 
Do. 
Do. 
Do. 
Do. 
Do. 
A comparison was then made of the action on Sarcina lutea . This 
organism was selected because it gives a characteristic, easily differen¬ 
tiated colony, and is about as sensitive to the action of chemicals as the 
pathogenic bacteria usually found in milk. Milk inoculated at 4.30 p. m. 
was left standing at room temperature till thd next morning, when it was 
placed in the incubator until noon before being treated. After^ stand¬ 
ing nearly 20 hours it was very acid. 
Table VIII. —Action of chlorin water , sodium hypochlorite, and calcium hypochlorite 
on Sarcina lutea 
Number of Sarcina lutea per plate, with — 
Active chlorin. 
Time acting. 
Chlorin water. 
Sodium hypo¬ 
chlorite. 
Calcium hypo¬ 
chlorite. 
Untreated. 
IOO 
IOO 
IOO 
O 
1 : 1000. 
2 hours. 
O 
0 
1:3000. 
...do. 
I 
0 
2 
1 : 6000. 
...do. 
10 
25 
5 
O 
1 : 10000 ... 
...do. 
I 
I 
No total count of the colonies on these plates was made. The photo¬ 
graphs of the plates show very clearly the effect of the chlorin from the 
three sources. (PI. 1, 2, 3.) 
A final comparison was made of the action upon B. coli communis . 
The milk was heavily inoculated at 4.30 p. m., practically the whole of 
a 24-hour culture being added to one quart. The culture was suspended 
