332 



SCIENTIFIC AGRICULTURE 



June, 1922 



Micro-organisms in Creamery Butter 



BY T. H. LUND 

 Dairy Bacteriologist, Ontario Agricultural College, Guelph. 



Following a preliminary study of the yeast 

 and mold content of twenty-two boxes of 

 creamery butter in the Fall of 1918, a more 

 detailed study of the microbial content of 

 creamery butter has been carried on in our 

 laboratories, as time and opportunity have 

 permitted. 



Our attention was first directed to this 

 subject by several Ontario creameries ship- 

 ping samples of their freshly-made butter, 

 weekly, to the laboratory of the American 

 Association of Creamery Butter Manufact- 

 urers in Chicago, to be analyzed for yeasts 

 and molds. Such analytical work was 

 carried on by the above Association for its 

 members under the direction of Dr. G. L. 

 McKay and Professor Bouska, and it was 

 felt that a similar service might with advan- 

 tage be made available, under the direction of 

 the Ontario Department of Agriculture, for 

 Ontario creameries desirous of availing them- 

 selves of it. As little detailed information 

 was available as to the methods and appli- 

 cations of this particular test, it was nec- 

 essary for us to try it out and see what we 

 could make of it, before recommending it 

 for routine use. 



Two other points we had in mind in tak- 

 ing up this investigation, namely, to study 

 the possibilities of the yeast and mold count 

 as a test, in butter grading work, for distin- 



guishing pasteurized from unpasteurized 

 cream butter, and also as a means for deter- 

 mining the germicidal efficiency of pas- 

 teurization in creameries where pasteurizers 

 were in use. A third point on which this 

 work eventually appeared to throw consider- 

 able light was upon "creamery sanitation" 

 particularly as it relates to cleanliness of ap- 

 paratus with which the cream comes in con- 

 tact after pasteurization, such as- conductor 

 pipes, coolers, pumps, churns, etc. 



The need for a test to distinguish pasteur- 

 ized from unpasteurized cream butter became 

 necessary with the introduction of Govern- 

 ment grading and the issuance of grade cer- 

 tificates for butter made fr^m "properly" or 

 "effectively" pasteurized cream. No scien- 

 tific definition being available in the case of 

 cream pasteurization to define or describe 

 just what is meant by the above indefinite 

 terms, it has been left largely to those in 

 charge of the grading work to set up stand- 

 ards and tests, which, in their opinion, form- 

 ed as a result of much practical experience, 

 would prove most satisfactory in the long 

 run to everybody concerned. This has re- 

 sulted in the adoption throughout Western 

 Canada and later in Ontario of the "Storch 

 Test" and the use of pasteurizing tempera- 

 tures and periods of holding sufficient to 

 ensure a "negative" reaction when a test of 



Date 

 Made 



5— 9 

 5—13 

 5—22 



6— 2 

 ()— G 

 6—14 



7— 7 



7— 8 

 7—17 

 7—28 



8— 4 

 8—10 



10 — 6 



