MODIFIED MILK AND MILK PRODUCTS 1 1/ 



Experiments have shown that the tubercle bacillus will remain 

 alive for considerable periods in butter, i.e. five months or longer 

 (Mohler, Washburn and Rogers). Teichert on the other hand 

 only found the bacilli alive up to 18 days. 



To detect tubercle bacilli in butter the inoculation method 

 is the only satisfactory one. The butter is placed in centrifugal 

 tubes which are stood in warm water at 42 C. until the butter is 

 completely melted. The material is centrifugalised when liquid, 

 and the sediment inoculated into guinea-pigs as described under 

 milk. It is difficult to keep the butter liquid during the centri- 

 fugalisation. 



It is important to remember that acid-fast bacilli may be 

 present in butter, and that not only may they interfere with 

 a simple microscopic examination, but that they may produce 

 pathogenic lesions closely resembling those caused by the 

 tubercle bacillus including the death of the animal. The Butter 

 bacillus isolated independently by Rabinowitsch and Petri from 

 butter is an acid-fast organism which morphologically resembles 

 the tubercle bacillus, and which will produce similar lesions in 

 guinea-pigs when injected intraperitoneally mixed with butter. 

 It can be readily distinguished from the tubercle bacillus by the 

 comparative rapidity of its growth on ordinary media, such as 

 nutrient-agar or glycerine-agar, a well-marked thick crinkled 

 growth being present after three to four days. 



In every case in which butter is being examined for 

 B. tuberculosis it is very important not only to make microscopic 

 films from the affected organs and demonstrate acid-fast bacteria, 

 but also to make cultivations upon glycerine-agar, to ascertain if 

 the butter bacillus is present and the cause of the lesions. It is 

 also advisable to subcultivate upon blood serum and egg medium 

 to isolate any tubercle bacilli present. 



Other pathogenic bacteria. The diphtheria bacillus appears to 

 have but a short life in butter, but the typhoid bacillus has been 

 shown by different observers to live for at least ten days. No 

 definite outbreaks appear to have been traced from their presence 

 in butter. 



To examine, liquefy at 42 C. and centrifugalise as for tubercle 



