INTRODUCTION 649 



south India. However, Henry and Kon^*^ were unable to confirm the 

 high figures for vitamin D in Indian butters. According to the latter 

 workers, the values for vitamin D in the three samples studied were as 

 follows (expressed in I.U./g. fat): Bangalore (sample 1), 0.56; Bangalore 

 (sample 2), 0.41; and Coimbatore, 0.29. Patwardhan^^^ cited a figure of 

 1.2 I.U. of vitamin D/g. fat in a Bangalore butter. It would therefore 

 appear questionable that butters from different areas exposed to moderate 

 or to excessive amounts of sunshine show any such marked variations in 

 vitamin D. According to the Heinz charts, ^^^ the figure of 35 I.U. /quart 

 of milk is based upon values for vitamin D in butter fat of 8 to 60 I.U./ 100 g. 



The vitamin D content of human milk has been found to be somewhat 

 higher than that of cow milk. Drummond and co-workers^*^ reported 

 an average figure of 60 I.U./quart in mother's milk. Greater amounts of 

 vitamin D occur in the colostrum than in the mature milk. This early 

 secretion contains six to ten times as much of the vitamin as in the milk 

 secreted later in the case of the cow,^^" and about three times the amount 

 in the case of human mothers. ^^^ 



The low concentrations of vitamin D in cow milk can be augmented in 

 commercial practice by any of several procedures. Thus, vitamin D may 

 be added directly to the milk in a suitable solvent such as propylene glycol, 

 to yield a product with a potency of 150 or 300 I.U./quart.^^^-^^^ A 

 second procedure which is frequently employed involves the direct irradia- 

 tion of the cow with sunhght or with artificial ultraviolet light, ^^"^-^^^ but 

 the method is of little importance commercially. 



Another procedure for increasing the vitamin D in milk which has con- 

 siderable application involves the direct irradiation of the milk. This is 

 the most economical method, but it is difficult to produce satisfactory 

 results, inasmuch as the milk acquires an unpleasant taste and odor if 

 over-irradiated.'^* Diemair'^* suggested several procedures for over- 

 coming this difficulty and increasing the amomit of vitamin D in the milk. 



186 K. M. Henry and S. K. Kon, /. Dairy Research 21, 81-82 (1954). 



18' V. N. Patwardhan, Personal communication, 1953; cited by K. M. Henry and S. K. 

 Kon, /. Dairy Research, 21, 81-82 (1954) 



188 H. J. Heinz, Nutritional Data, Pittsburgh (1950). 



183 J. C. Drummond, C. H. May, and N. E. G. Richardson, Brit. Med. J., 1939, II, 

 757-760. 



18" J. van Niekerk and M. S. C. Bliek, Acta Brevia Neerland. Physiol. Pharmacol. Micro- 

 biol., 9, 25~2Q (1939). 



1" T. F. Zucker, Avi. J. Pub. Health, 23, 10-18 (1923). 



'92 D. J. Barnes, J. Mich. State Med. Soc, 22, 242-246 (1933). 



1" K. G. Weckel and H. C. Jackson, Food Research, 1, 419-426 (1936). 



19* W. Diemair, Chem. Fabrik, 14, 51-54 (1941). 



