94 MILK PRODUCTS 



found that two tests devised for detection of 

 rosin-oil can be satisfactorily adapted to detec- 

 tion of palm oil. Success depends on several 

 points. The sample must be kept in a cool 

 dark place until used, filtered at a temperature 

 not above 70°, the heating as brief as possible, 

 and promptly tested. The reagents must be/ 

 pure and colorless. Cochran finds that annatto 

 will simulate palm oil in these tests, and henc^ 

 the absence of the former must be assured 

 (see above) before inferring the presence of the 

 latter. 



Halphen method. — 100 c.c. of the filtered fit 

 are dissolved in 300 c.c. petroleum spirit and 

 shaken out with 50 c.c. of potassium hydroxid 

 solution (o. 5 % of hydroxid) . The water is drawn 

 off, made distinctly acid with hydrochloric acid, 

 and shaken out with 10 c.c. of carbon tetrachlorid. 

 This solution is drawn off, and part of it tested 

 by adding to it 2 c.c. of a mixture of i part crys- 

 tallized phenol in 2 parts carbon tetrachlorid. To 

 this add 5 drops of hydrobromic acid (sp. gr. 1.19). 

 The test is best performed in a porcelain basin and 

 the contents mixed by agitating gently. Palm oil 

 gives almost immediately a bluish-green liquid. 



Liebermann-Storch method. — 10 c.c. of the 

 filtered fat are shaken with an equal volume of 

 acetic anhydrid, one drop of sulfuric acid (sp. 

 gr. 1.53) is added and the mixture shaken for 



