64 



COAL-TAR COLORS USED IN FOOD PRODUCTS. 



Of these 32, 16 were on the United States market in the summei 

 of 1907 and their composition disclosed; they are presented in th 

 following table, together with the number of dealers, out of a possible 

 12, offering them for sale. 



Distribution of "favorable" colors on the American market in 1907. 



From among these 16, six of the seven permitted colors of Fooc 

 Inspection Decision No. 76 were selected. The process of selection 

 and of elimination is described on page 166. 



CLASSIFICATION ACCORDING TO CHEMICAL COMPOSITION AND 



SUITABILITY. 



In the following table the chemical composition of the substances 

 corresponding to the Green Table numbers is given, and their classi- 

 fication according as the literature is regarded as being (1) unfavor- 

 able, (2) favorable, or (3) contradictory in regard to the color. The 

 colors are also arranged in the groups to which they belong chemically, 

 so that this table shows: (1) The number of groups reported on in the 

 literature, (2) the number and composition of members of each group 

 so reported on, and (3) the interpretation here placed upon such 

 reports in literature. This table is given in the expectation that it 

 will be of use to chemists and physiologists. 



Opinions as to suitability, classified according to groups and chemical composition. 

 (Tie chemical nomenclature is that of the Green Tables; " a " is used for alpha and " b " for beta.) 



Unfavorable. 



Favorable. 



Contradictory. 



t NITEO COLORS. 



1. Symmetrical trinitrophenol. 



2. Dinitro o and p-cresol. 



3. Dinitro-a-naphthol. 



6. Hexanitro-diphenylamin. 



MONOAZO COLORS. 



78. Methyl-benzenyl-amido-thio- 

 xylenol-azo-a-naphthol di- 

 sulphonic acid. 



94. Benzene-azo-pyrazalone-car- 

 boxy-disulphonic acid. 



97. Sulpho-o-toluene-azo-b- naph- 



4. Dinitro-a-naphthol-b-mono- 



sulphonic acid. 



5. Dinitro-a-naphthol-a- mono- 



sulphonic acid. 



28. p-nitro-benzene-azo-a - naph- 

 thylamin p-sulphonic acid. 



65. a-naphthalene-azo-b-naph- 



thol-disulphonic acid. 

 85. p-sulphobenz ene-azo-a- 



naphthol. 

 89. p - sulphobenzene - azo - di - 



phenylamin-su 1 p h o n i c 



acid. 

 92. Diphenylamin yellow with 



nitro-diphenylamin. 



8. Amido - azo - benzene-di- and 



monosuiphonic acid. 



9. Amido - azo - toluene - disul 



phonic acid. 

 11. Benzene-azo-b-naphthol. 



13. Benzene-azo-b- naphthol - b 

 sulphonic acid. 



14. Benzene-azo-b-naphthol 

 sulphonic acid G. 



di- 



