1 76 FERMENT A TION IN MILK 



(4.) Bitter Milk 



From an economic point of view this " milk anomaly " is 

 perhaps the most serious with which the dairy bacteriologist 

 may have to deal, for, once the organism gains admittance to a 

 dairy it is somewhat difficult to eradicate, and although from the 

 intermittent nature of the disease one would be led to suppose 

 that its development is accelerated or retarded by certain climatic 

 conditions, yet the frequent and continued recurrence of the con- 

 dition after considerable lapses of time are often a cause of serious 

 loss to the dairy industry. The defect is rarely observed in fresh 

 milk, owing probably to the time required for the due develop- 

 ment of the organism, but appears chiefly in the cream set apart 

 for butter-making purposes, in which it causes the development 

 of a peculiar bitter taste which makes both it and the resultant 

 butter unfit for alimentary purposes. 



In the Report of the Dairyman's Association of Ontario for 

 1900, it is stated that during the first year the creameries in the 

 North-West territories were working, the milk had no bad flavours, 

 but that latterly bad and bitter flavours had developed. This was 

 attributed by certain Canadian authorities to insanitary conditions 

 of milk " factories," and by others to the importation of micro- 

 organisms able to set up bitterness in milk. 



The disease has been attributed to several micro-organisms, as 

 well as to irregularity of diet in the cow, and the question has 

 been closely studied by various workers, especially by Weigmann, 

 Hueppe, Freudenreich, and Bleisch. 



Hueppe has suggested that some bitter conditions of milk are 

 due in part at any rate to a proteid decomposition, the final pro- 

 ducts of which are bitter.^ Peptones may be demonstrated by the 

 biuret reaction. Such substances may act like alkaloidal poisons 

 upon animals, and are produced by bacteria frohi the albuminoids 

 of milk. It is probable that these or similar conditions give rise to 

 benzine derivatives, the most important of which is diazo-benzine 

 or tyrotoxico7i, isolated by Vaughan of Michigan. Spasmotoxine 

 is a similar body found by Brieger in putrefied milk. Various 



^ We have on more than one occasion met with milk which became bitter 

 after sterilisation, particularly some time after sterilisation. It may be that 

 such bitterness is due to toxic properties remaining in the milk as the result of 

 bacterial activity previous to sterilisation, and possibly to proteid decomposi- 

 tion. Hueppe has met with a similar experience, and attributes the change to 

 ineffectual sterillisation. / 



