UNITED STATES DEPARTMENT OF AGRICULTURE 
m BULLETIN No. 361 $■» 
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Contribution from the Bureau of Animal Industry 
A. D. MELVIN, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
June 29, 1916 
COMPARISON OF THE BACTERIAL COUNT OF MILK 
WITH THE SEDIMENT OR DIRT TEST. 
By H. C. Campbell, 
Expert in Milk Hygiene, Pathological Division. 
Utility of the sediment test.. 
Object of the work 
Outline of experiment 
Method of collecting samples,. 
Details of the experiments. . . 
CONTENTS. 
Page. 
1 
2 
2 
3 
Page. 
Details of the experiments— Continued: 
Comparisons with unfiltered market milk 3 
Comparisons "with filtered milk 5 
Conclusions 6 
References to literature & 
UTILITY OF THE SEDIMENT TEST. 
The sediment or dirt test has been used for some time as a means 
of detecting risible dirt in milk. It was first applied in Europe to 
grade the milk as it arrived at the milk-receiving stations. After 
the milk had passed through the cotton disks they were cut in two r 
one part being kept for reference and the other mailed to the pro- 
ducer. In this manner it was found to be valuable in inducing the 
farmer to produce cleaner milk. 
During the past few years the sediment test has gained great favor 
among milk inspectors in this country. They say it has been of great 
value, as they can actually show the farmer when his milk is insanitary 
and in this way better fix a standard of prices at the milk-receiving 
stations. Until recently the grading of milk and cream at receiving 
stations was based entirely upon such tests as those for per cent of 
fat, acidity, odor, etc. No test was used whereby any information 
could be gained regarding the sanitary conditions under which the 
milk was produced. 
Since the discovery of the sediment or dirt test the grading or 
judging of milk at receiving stations has been of two kinds, chemical 
and hygienic. It has been the opinion of inspectors that when milk 
contained sediment or dirt it was insanitary, but until the discovery 
26052°— Bull. 361—16 
