TAINTS AND DEFECTS OF BUTTER 355 



Weigmann and his pupils have shown that the dung 

 of cows fed with large amounts of turnips contain certain 

 varieties of Pseudomonas belonging to the c0//'-group of 

 bacteria which are able to give rise to the taste and 

 odour of turnips in varying degree when introduced into 

 milk, cream, and butter. Presumably these gain access 

 to the milk in particles of dung, for when the udders of 

 the cows feeding on turnips are brushed and washed and 

 the dung disinfected with lime the milk and the cream 

 and butter derived from it do not develop the turnipy taste. 

 These organisms produce the strongest development 

 of the objectionable taste when working in combination 

 with varieties of Streptothrix and certain fungi, especially 

 a form of Penicilliiim brevicatile. 



Foul odours may arise in butter which is contaminated 

 with dirty water, dung, and other materials containing 

 Bact. niycoides, Bact. vulgatus, Bs. fluorescens liquefaciens, 

 and other organisms of the putrefactive group. 



Bitterness may be due to food of the cow or the activity 

 of bacteria. 



Fishy and cheesy odours and tastes have, in certain 

 instances, been traced to the work of moulds and species 

 of Torula (p. 394). 



5. Salt in Butter. The addition of salt has a very 

 beneficial influence upon the keeping quality of butter 

 and in small amounts assists in preserving it free from 

 taints. 



The number of organisms present in salted butter 

 increases much more slowly, and the ultimate decrease 

 which occurs begins at an earlier period than in unsalted 

 samples. 



This is evident from the following table given by 

 Fettick I 



