Bulletin 145 Julx 1905 



Ontario Agricultural College and Experimental Farm. 



BUTTER PRESERVATIVES. 



By H. H. Dean, Professor ok Dairy Husetandry ^^'Hfc' 

 AND R. Harcourt, Professor of Chemistry. "'" 



Butter is composed of fat, water, curd, and a small amount of min- 

 eral matter. Fat is the most important constituent, and forms 84 to 87 

 per cent, of the butter. Butter fat is an extremely complex substance, 

 composed of fatty acids in combination with glycerine. It differs from 

 other fats, such as lard, tallow, etc., in that it contains a larger number of 

 these glvcerides. Besides the glycerides of the insoluble and non-vola- 

 tile acids found in all fats, butter contains notable quantities of the glycer- 

 ides of soluble and volatile acids. Some of these acids have a decidedly 

 disagreeable odor, and, if by any means the glycerides containing these 

 acids are decomposed, very strong rancid odors are developed. Further- 

 more, some of the fats are unsaturated compounds, which more or less 

 rapidly combine with the oxygen of the atmosphere and thus set in motion 

 changes which may not only destroy the pleasant aroma of good but- 

 ter, but may also produce the disagreeable rancid smell common to bad 

 butter. 



The amount of curd in butter is not large, and, while it readily under- 

 goes purtrifactive changes, does not appear to directly affect the keeping 

 quality of the butter.* It serves, however, as food for the micro-organ- 

 isms which cause the change and thus tends indirectly to produce bad 

 flavors. 



It is thus evident that the constituents of butter in their natural state 

 are all delicate substances, some of which, or a combination of the whole, 

 produce the peculiar aroma of good butter, and that the bad flavors are 

 produced partly, at least, through the decomposition and oxidation of 

 these substances. Most of these changes are doubtless due to the action of 

 ferments which also produce compounds of an unpleasant nature. In 

 addition to this, butter may have undesirable taints due tu improper feed- 

 ing of the cows, lack of care in treatment of the milk and cream, and to 

 carelessness in the manufacture of the butter. Many of the faults of 

 butter, due to these various causes, can be overcome. It is only by 

 exercising the utmost care in every deiail, from the production of the 

 milk to the manufactured butter, that an article of the desired quality 

 can be secured. But all butter, no matter how carefully it is made, will 

 go "off flavor" in a comparatively short time. 

 •College Report, 1902, page 39. 



