UNITED STATES DEPARTMENT OF AGRICULTURE 



StJ^'^'-J'U 



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 



WITH THE SEDIMENT OR DIRT TEST. 



By H. C. Campbell, 

 Expert in Milk Hygiene, Pathological Division. 



CONTENTS. 



Utility of the sediment test 1 



Object of the work 2 



Outline of experiment 2 



Method of collecting samples 3 



Details of the experiments 3 



Details of the experiments— Continued: 



Comparisons with unfiltered market milk 3; 



Comparisons with filtered milk 5 



Conclusions 6 



References to literature 6 



UTILITY OF THE SEDIMENT TEST. 



The sediment or dirt test has been used for some time as a means 

 of detecting visible dirt in milk. It was first applied in Europe to 

 grade the milk as it arrived at the milk-reoeiving stations. After 

 the milk had passed through the cotton disks they were cut in two^. 

 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 



