414 Bacteria in Relation to Country Life 



pies. In another instance, an examination of one hun- 

 dred samples of butter selected in Stuttgart showed that 

 living tubercle bacilli were present in nearly one out of 

 every ten samples. There is, therefore, more or less 

 danger of transmission of tuberculosis by means of 

 butter, and the pasteurization of cream in butter- 

 making, whenever practicable, must be regarded as a 

 commendable practice from the standpoint of public 

 hygiene. In the case of typhoid and diphtheria, on the 

 other hand, the danger of transmission in butter, if it 

 exists at all, can be only slight. The germs of these 

 diseases do not seem to occur in market butter. Typhoid 

 bacilli, purposely added, disappeared gradually and 

 could not be detected at the end of ten days. 

 Tubercle bacilli also gradually disappear in stored but- 

 ter, although they are hardier than the typhoid germs 

 and may persist for weeks, perhaps for months. 



Butter faults. — Occasionally butter acquires unde- 

 sirable characteristics, quite different from the ordinary 

 development of rancidity. The objectionable changes 

 known as butter faults or butter diseases may affect 

 the appearance and taste of the butter, giving rise to 

 mottled, putrid, bitter or tallowy butter. Such faults have 

 been traced to microorganisms that may be derived from 

 the cream or from other sources. .Samples of inferior 

 cream produced in a filthy environment often contain 

 species of bacteria that later develop in the butter and 

 destroy its value as a food product. The pasteurization 

 of such cream undoubtedly improves the keeping qual- 

 ity of the butter made from it. 



Not infrequently, butter faults have their origin not 



