ANALYSES OF CERTIFIED PERMITTED COLORS. 



207 



for human consumption as food. This stand is fully justified by the 

 quality of the coal-tar dyes offered as food colors on the United States 

 markets as described in the foregoing pages. That such control is 

 not only practical, but practicable, is fully proved by the fact that 

 more than 20.5 tons (41,000 pounds) of coal-tar food dyes have been 

 so controlled, examined, and certified under the food inspection deci- 

 sions hereinbefore mentioned. 



The figures are expressed in parts per hundred of actual color 

 contained in the dye and not in parts per hundred of the total 

 substance. The numbers at the head of the columns are the num- 

 bers in the Green Tables. 



Tentative limits of composition suggested for permitted colors. 

 (Parts per hundred of actual color.) 



In addition to these there are the following requirements applicable 

 to all colors : 



1. The absence of admixed dye must be convincingly demonstrated by suitable 

 test. 



2. Arsenic. Test 17 of the United States Pharmacopoeia, 1900, applied to so much 

 of the specimen as represents 3.5 grams of actual dye must give a negative response. 

 Such negative result must be reenforced by a check test identical with the test on the 

 dye with the addition of 0.005 mg of arsenic (As 2 3 ) to the dye prior to treatment, 

 and this check test must produce a positive result for the presence of arsenic. Igni- 

 tions in the preparation of the material for the test must be made in porcelain. 



Any other mode of testing which is demonstrated to be capable of detecting 0.005 

 mg added arsenic (AsjOg) in so much of the specimen as represents 3.5 grams of actual 

 color will, of course, be accepted. This quantity, however, is only tolerated tenta- 

 tively pending further investigations relative to the complete, or practically com- 

 plete, elimination of arsenic from foods, especially those which are largely used by 

 children, such as candies. 



3. Heavy metals. Test 121 of the United States Pharmacopoeia as revised May 1, 

 1907, using so much of the specimen as represents one part of actual dye must give a 

 negative response for all metals except iron, which may be present in amounts not in 

 excess of 0.005 per cent of iron based on the dye actually present in the specimen. 



4. None of the dyes offered for certification shall contain any Glauber's salt or 

 sodium sulphate in any form, nor shall they contain any added sugar, dextrin, or 

 other loader, filler, or reducer for any purpose whatsoever, and convincing proof of the 

 absence of any or all of them must be submitted. 



