BUTTER STORAGE 459 



into storage, the development of the storage flavors may be very 

 slight. Butter of poor quality usually shows very great de- 

 terioration in- storage, the flavor defects may be numerous and 

 often one flavor may succeed another as storage progresses. An 

 oily flavor may develop into a metallic flavor and this in turn 

 may give way to fishy flavor, etc. 



3. The quality of the cream from which the butter is 

 made, largely governs the keeping quality of the butter in 

 storage. Butter made from a poor quality of cream cannot be 

 expected to withstand rapid and intense deterioration in 

 storage. 



4. The analysable chemical changes which butter undergoes 

 in storage, are very slight, even in butter which has yielded to 

 most pronounced flavor changes. The exact changes, and the 

 constituents of the butter which are changed, that are respon- 

 sible for the development of specific flavor defects have not been 

 determined in the great majority of cases. It is assumed with 

 reasonable certainty however, that rancidity and tallowiness 

 are due to cleavage of the butterfat, rancidity through bacterial 

 or enzymic action or both, and tallowiness through chemical 

 action. The characteristic flavor of cold storage butter and its 

 derivations such as oily, metallic and fishy flavors, are generally 

 assumed to result from the decomposition of the non-fatty con- 

 stituents of butter. 



5. The most active agents bringing about deterioration of 

 butter in cold storage appear to be cream with a high acid con- 

 tent, the presence in cream and butter of metals, such as cop- 

 per and iron, and their salts, the air incorporated in the butter 

 and bacteria and enzymes ; though the influence of microorgan- 

 isms is considered of indirect rather than of direct nature. 



6. In order to insure, with reasonable certainty, butter of 

 good keeping quality, and minimum deterioration in commer- 

 cial cold storage, the butter should be made from cream of good 

 quality and low acidity, transported in cans that are free from 

 rust, and handled in vats, pasteurizers and conduits properly 

 tinned and the surfaces of which are kept bright and free from 

 accumulations of oxidized or dissolved metal, the pasteurization 

 should be thorough and preferably by the flash process at 176 

 F. or over, or the holding process at 145 F. for 30 minutes, the 



