334 



SCIENTIFIC AGRICULTURE 



June, 1922 



When sampling is done in the above manner 

 it will be seen tliat surface contaminating 

 organisms (molds particularly) are avoided, 

 the examination being made on butter taken 

 from the interior of the package, the micro- 

 bial content of which may be very different 

 from that of butter taken from the surface 

 layer, the latter at times being very heavily 

 contaminated with molds, while the butter 

 in the .interior of the package may be entirely 

 free from them. 



After the samples are secured they are 

 refrigerated and shipped to the laboratory 

 (once a week in case of the Grading Station 

 samples) where cultures of them are made 



on the day of receipt or the following day. 



For culture medium a wort agar of the 



following composition was worked out and 



adopted after considerable experimentation: 



Wort 400 c.c. 



Tap water .... 600 c.c. 



Agar 15 grams 



This has been acidified by the addition of 

 4 c.c. of sterile 5 per cent, lactic acid per 

 100 c.c. of medium immediately before plat- 

 ing, to inhibit bacterial growth. Colonies 

 have been picked off these acidified wort 

 agar plates from time to time and examined 

 microscopically, but in no case have any bac- 

 terial colonies been found. 



TABLE III. 



Oidiurn and Yeast Counts of Butter, Domini on Scoring Contest, 1920. 

 93 non-reactors with Storch Test, June, J uly, Sept. and Oct. entries. 



NOTE: Numbers above arc counts per c.c. of butter. 



Eirst column — Oidiuni lactis mold. Second column — Yeasts. 



* Over 100,000 per c.c. 



