EXAMINATION OF CONDENSED MILK AND 

 CURDLED MILK. 



I. CONDENSED MILK. 



The examination of condensed milk is made accord- 

 ing to the methods described for ordinary milk. A 

 Slated amount of the condensed preparation is diluted 

 with a given amount of water and the previously de- 

 scribed methods employed. The estimation of dry mat- 

 ter obviously is made with undiluted milk. 



To prove the presence of diluted condensed milk in 

 fresh milk use is made of the fact that a part of the sugar 

 is caramelized in evaporation, thereby becoming optically 

 inactive. Therefore the estimation of the quantity of 

 sugar by use of the polariscope gives lower results than 

 the volumetric or gravimetric methods of analysis. Usu- 

 ally the difference between the two methods in fresh milk 

 is never more than 0.15 per cent. (Droop-Richmond.) 



II. CURDLED MILK. 



Curdled samples are examined according to the usual 

 methods. For the determination of fat the curd is dis- 

 solved bv adding a few drops of a dilute solution of po- 

 tassium or sodium hydrate. The specific gravity is best 

 ascertained by a method of Weigul's as follows : 



A definite volume of the milk (Vm) is mixed with a 

 known volume of ammonia (\'a) of known specific grav- 

 ity. By shaking, the curd dissolves completely. The 

 volume of the solution (\'s) is equal to Vm + ^'3- The 

 specific gravity of the solution (Ds) is determined by 

 means of an accurate areometer. From the data thus 

 obtained the specific gravity (Dm) of the curdled milk 

 mav be calculated by the formula : Dm=l2^^?=l2^2± 



