Bacteria and Butter Making. 157 



culiar to them being absorbed directly by the milk and 

 thus transferred to the butter. Weigmann traced a sim- 

 ilar flavor to certain bacteria 'that entered the milk from 

 bam filth. 



Cowy odor in butter. There is sometimes to be noted 

 an odor in butter as in milk that resembles that of the 

 cow stable. Usually this defect has been ascribed to the 

 absorption of these odors directly by the milk. Organ- 

 isms have also been described that impart to the butter 

 a very similar odor. Bitter butter may be due to the 

 feed that is consumed by the cow, or it may be due to 

 those forms of bacteria that produce a bitter fermenta- 

 tion of the milk. 



Other abnormal flavors. Among the numerous ab- 

 normal flavors that have been noted in butter is one of 

 quite frequent appearance, the so called " fishy" flavor. 

 It is now believed by many that this flavor is due to the 

 presence of small amounts of iron or copper salts that 

 have been introduced into the milk from utensils from 

 which the protective coating of tin has been worn. If 

 the milk or cream stored in such utensils develops any 

 marked degree of acidity, the acid will dissolve a small 

 amount of the iron or copper. The fishy flavor has not 

 been found in sweet-cream butter as would be expected 

 from the above explanation. In fresh butter a metallic 

 taste is sometimes present. It is believed by some that 

 on storage this flavor changes to the fishy flavor. 



All utensils used for the storage of milk and cream 

 should be kept in good condition so as to prevent the 

 acid milk or cream from coming in contact with iron or 

 copper. 



Moldy butter. A defect that causes a great amount 

 of loss is the development of mold on the surface of the 



