128 MILK [vn 



may be mentioned that a species of bacteria has been 

 found which produces an odour and taste similar to 

 that produced by the feeding of roots. Butter made 

 by the use of this kind of bacteria acquired this root 

 taste in about two weeks. 



Number of Bacteria in Butter. Interesting 

 investigations on the number of bacteria present in 

 butter have been recently carried out by Lafar on 

 different samples of Munich butter. In one gramme 

 (about the -^g-th of an ounce), taken from the centre 

 of a pat of butter, nearly two and a half millions 

 were found. Equal amounts of butter, taken from 

 more exposed portions of samples, were found to 

 contain far larger numbers in one case as many as 

 forty - seven and a quarter millions being found. 

 Taking the average of a number of investigations, 

 Lafar concluded that a gramme of butter contains 

 from ten to twenty million bacteria. 



The few experiments which have been carried out 

 on the subject show that artificial butter contains 

 fewer bacteria, and those of a different nature, than 

 natural butter. The presence of pathogenic bacteria 

 in butter is dangerous, for the reason that butter 

 cannot be submitted to sterilisation, but has to be 

 eaten in the raw state. Lafar is of the opinion that 

 typhus and cholera bacteria would die in butter in 

 from five to seven days, and those causing tuber- 

 culosis lose their power of doing harm in twelve days. 



