712 VETEEINAEY HYGIENE 



Bitterness in milk is due to an organism acting as a 

 ferment on the proteids of milk, and producing peptone and 

 other products of proteid change, to which in all probability 

 the bitterness is due. The hay bacillus can, it is said, bring 

 about this change. 



Alterations in milk affecting its colour are also known 

 to result from organisms ; thus blue milk results from the 

 action of the Bacillus cyanogenus, a change which occurs in 

 milk on standing, and in which the presence of lactic acid 

 is an essential. Eed milk may be due to Micrococcus 

 -prodigiosus or other pigment-forming bacteria. Yellow-milk 

 is caused by the Bacillus synxantlius. In addition to the 

 above, green and violet pigments in milk are found as the 

 result of bacterial action. 



None of these organisms exist in the milk when drawn 

 from the body, but are the result of subsequent con- 

 tamination. 



Milk may readily be affected by powerfully smelling 

 substances in the food (see pp. 185, 159, 183, 184, 262), 

 turnips being perhaps the most common cause of taste. 

 Besides this it can absorb odours from without, such as 

 may be met with in badly ventilated cow-sheds or defective 

 dairies, or from the use of carbolic acid as a disinfectant, 

 or the presence of ensilage in the cow byre. The capacity 

 milk possesses for absorbing gases or volatile substances 

 is remarkable, in this respect it has been likened to a 

 sponge ; hence the necessity for the most thorough hygienic 

 surroundings in the cow-shed and dairy. 



The Care of Milk. 



The care of milk essentially belongs to the medical 

 officer ; but it is important that our knowledge of this 

 matter should be equal to his, for the cow may be blamed 

 when the fault lies with the man. Still, we fully recognise 

 that the care of milk, its storage, distribution, and sale, 

 come entirely within the duties of the Medical Officer of 

 Health, as completely as the cow and cow-house belong to us. 



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