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A MANUAL OF BACTERIOLOGY 



Another method for sterilising milk is the Budde process, 1 

 in which the milk, after the addition of hydrogen peroxide, 

 is heated for three hours to 52-53 C. All. non-sporing 

 organisms are destroyed, and the added hydrogen peroxide 

 is decomposed into H 2 O and O 2 . Ultra-violet light is 

 inefficient owing to the opacity. Sterilisation by an electric 

 current has recently been reported to be successful. 



The thermal death-point of pathogenic organisms in milk is 

 as follows : 2 



The thermal death-point of the tubercle bacillus, especially in 

 milk, has been the subject of some controversy (see also p. 376). 

 De Man found that an exposure of fifteen minutes at 65 C. was 

 necessary to destroy the infective properties of tuberculous milk. 

 Bang, of Copenhagen, considers that pasteurisation cannot 

 always be relied upon, and recommends that milk should be 

 heated to 85 C. The writer found that the vitality of the 

 ordinary non-virulent laboratory cultures was destroyed by a 

 temperature of 60 C. acting for ten minutes, and that the infective 

 properties of tuberculous sputum, tested on guinea-pigs, were 

 destroyed by a temperature of 65 C. acting for fifteen minutes 

 in five out of six instances. Woodhead's experiments (First 

 Royal Commission on Tuberculosis) gave irregular results which 

 seem to be explained by Theobald Smith's careful work. 3 This 

 showed that tuberculous milk was rendered non-infective by 

 heating to 60 C. for ten to fifteen minutes, provided there was 



1 Hewlett, Lancet, 1906, vol. i, January 27. 



2 Rosenau, Hygienic Lab., Washington, Bull. 42, 1908. 



3 Journ. Exper. Med., vol. iv, 1899, p. 217. 



