n8 MILK AND DAIRY PRODUCTS PART 



five minutes is faintly green, which deepens, but never acquires 

 the characteristic blue shade obtained in the first case. 



By means of this method quantities of saccharose smaller 

 even than 0'05 per cent, can be detected. 1 



The Detection of Lime in Milk. 



Two hundred and fifty c.c. of milk at 15 C. are shaken with 

 10 c.c. of hydrochloric acid (10 per cent.) and allowed to stand for 

 half an hour at ordinary temperature. After this the mixture 

 is filtered, and the first portion of the filtrate returned to the 

 filter. The filtration proceeds very slowly, and the filter should 

 be covered to prevent evaporation, just as is done in the 

 preparation of milk serum. 



One hundred and four c.c. of the filtrate, equivalent to 100 c.c. 

 of milk, are poured into a 200 c.c. flask, 10 c.c. of 10 per cent, 

 ammonia added, and the flask filled to the mark with water 

 at 15 C. After standing for half an hour the solution is filtered 

 through a folded filter, the first portion of the filtrate being 

 collected separately and poured back on to the filter. One 

 hundred c.c. of this filtrate, equivalent to 50 c.c. of milk, are 

 tested with 10 c.c. of 5 per cent, ammonium oxalate solution, 

 and the determination of lime made in the usual way, but 

 without warming the liquid. 



Where cream is to be examined the procedure is as follows : 



Two hundred c.c. of cream at 15 C. are shaken with 8 c c. of a 

 10 per cent, solution of hydrochloric acid and left to stand for 

 half an hour, after which the serum can be filtered through 

 a folded filter, the usual precautions being taken to collect the 

 first portions separately and return them to the filter. Then 

 52 c.c. (), equivalent to 50 c.c. of cream, are transferred to a 

 100 c.c. flask, 5 c.c. of 10 per cent, ammonia added, the flask 

 made up to the mark and allowed to stand half an hour, then 

 the contents filtered. Five c.c. of the filtrate, equivalent to 

 25 c.c. of cream, are allowed to stand overnight with 10 c.c. of a 

 5 per cent, solution of ammonium acetate. The estimation of 

 lime is similar to that described above for milk, and the result 

 must be multiplied by four. 



1 Latterly, Rothenfusser (Zeitschr. fur Untzrsuchung der Nahr- und Genuss- 

 mittel, 1909, Vol. XVIII, p. 145) has worked out a method for the detection 

 of saccharose in milk, which is simpler and gives very good results. Its 

 sensibility is greater than the above-mentioned. 



