BACTERIA IN BUTTER 



389 



Tubercle bacilli have also been found in oleomargarine. Briscoe 

 and MacNeal tabulated the analysis of 209 samples, 4.3 per cent, 

 of which were found to contain tubercle bacilli. 



The longevity of tubercle bacilli in butter is even greater than that 

 of B. typhosus, for Schroeder and Col ton demonstrated their pres- 

 ence in butter which had been kept for one hundred and sixty days ; 



130- 

 120- 

 110- 

 100- 

 90- 

 80- 

 70- 

 60- 

 50- 



30- 

 20- 

 10- 



Commercial score 

 Bacteria content 



10 20 30 40 50 60 70 80 90 100 110 120 130 



Days 



FIG. 47. Bacteria content and commercial score of Cheddar cheese. (After Harding 



and Prucha, 1903.) 



and contrary to prevailing opinion Mohler, Washburn, and Rogers 

 found tubercle bacilli were not devitalized by cold storage, and in 

 salted butter they were found to retain their virulence for six 

 months. 



Diphtheria bacteria have been found in butter, and an outbreak 

 at Lewiston, Minnesota, was believed to have been caused by eating 

 infected butter. There had been no diphtheria in the place until a 



