2i 4 MILK AND DAIRY PRODUCTS PART 



that of Seliwanoff as modified by Carlsson, 1 which is carried out 

 as follows : 10 c.c. of milk are taken, or 0*5 g. of milk sugar 

 dissolved in 10 c.c. of water, and warmed in a test-tube with 

 50 mg. of resorcin and 0*5 c.c. of hydrochloric acid (25 per 

 cent.). In the presence of cane sugar a red coloration is 

 obtained after boiling for a few minutes. With less than 1 per 

 cent, of cane sugar the reaction is somewhat indistinct, but for 

 more than 1 per cent, it is very reliable. Still more sensitive 

 is the test employed by Rothenfusser for detecting the 

 saccharose of calcium saccharate when the latter has been 

 mixed with milk or cream (p. 117). 



The condensed milk must also be examined for preservatives 

 other than cane sugar. 



IV. DESICCATED MILK on MILK POWDER. 



The majority of samples of desiccated milk prepared up to 

 the present do not give by any means a perfectly homogeneous 

 milk-like emulsion when mixed with the prescribed quantity of 

 water. On account of the difficulty of getting a satisfactory 

 average sample from such an artificial mixture it is best to 

 analyse the dry substance. 



The water is determined by drying a few grams of the 

 powder in a drying bottle at 100 to 105 C., and the fat either 

 by the Soxhlet or Rose-Gottlieb method. According to 

 H. Haupt 2 this is best done by taking 1 g. of air-dry powder 

 and shaking it vigorously in a Gottlieb tube for three to five 

 minutes with 9 c.c. of warm water. Then 2 c.c. of 20 per cent, 

 ammonia are added and the shaking repeated until complete 

 solution has been effected. After one or two minutes 10 c.c. of 

 96 per cent, alcohol are added, the mixture again shaken, and 

 the determination completed in the ordinary way. 



The protein is generally determined by Kjeldahl's method, 

 and the nitrogen multiplied by 6 '37. To determine the milk 

 sugar the dried milk must first be dissolved in water, the 

 quantities which are directed being taken, and when by warming 

 and stirring a satisfactory solution is obtained it is treated like 

 ordinary milk. Some milk powders contain cane sugar, and to 



1 Pharm. Centralblatt, 1903, p. 133. 



2 . Zeitschr.filr Unt. d. Nahr.- u. Genussmittel, 1906, Vol. XII. p. 217. 



