MILK 



117 



petroleum ether, which does not attack the colouring matter or 

 the paper fibre. 



In this way many of the usual colouring substances used 

 in the dairy can be detected, but there are several that are 

 not. 



VI. ADDITION OF SACCHARATE OF LIME. 



Latterly it has become a not uncommon practice to add 

 saccharate of lime, which is sold under various names, to milk 

 and cream. This material preserves the milk or cream and also 

 increases their viscosity, so giving them the appearance of 

 being richer in fat. Cream treated in this way is more easily 

 whipped, and it has also a deeper yellow colour. Naturally 

 such an addition must be regarded as an adulteration, and 

 Baier and Neumann 1 have worked out a good method, which 

 has been well tested by Luhrig. 2 



The Detection of Saccharose in Milk to which Saccharate of Lime 

 has been added. 



Twenty-rive c.c. of milk or cream are shaken in a small Erleri- 

 meyer flask with 10 c.c. of a 5 per cent, solution of uranium 

 acetate, allowed to stand for five minutes, and filtered through 

 a folded filter. 



The filtrate, as a rule, is perfectly clear, and does not need to 

 be poured through the filter again. To 10 c.c. of the filtrate 

 (with cream the total filtrate is usually not more than 10 c.c., 

 so all of it must be used) 2 c.c. of a cold saturated solution of 

 ammonium molybdate are added, and 8 c.c. of HC1 (1 part 25 per 

 cent, acid to 7 parts water). This mixture is then shaken, and 

 placed in a water-bath at 80 C. for five minutes. At the end 

 of this time the presence of saccharose in the milk or cream is 

 indicated by the solution becoming more or less blue, according 

 to the amount of saccharose present. If the test-tube is allowed 

 to remain for a longer time in the water-bath the blue colour 

 becomes still deeper. At the end of ten minutes it is deep 

 blue, whereas with unadulterated milk the colour at the end of 



1 Zeitschrift fiir Untersiichnwj der Nahr- mid Genussmittel, 1908, Vol. XVI, 

 p. 51. 



' 2 Molkerei-Zeituny, Hildesheim, 1909. 



