All food use Coloring Agents.
Blue 2 (artificial color)
The color additive FD&C Blue No. 2 is principally the disodium salt of 2-(1,3-dihydro-3-oxo-5-sulfo-2 H-indol-2-ylidene)- 2,3-dihydro-3-oxo-1H-indole-5- sulfonic acid with smaller amounts of the disodium salt of 2-(1,3-dihydro-3-oxo-7-sulfo-2 H-indol-2-ylidene)-2,3-dihydro -3-oxo-1H-indole-5-sulfonic acid and the sodium salt of 2-(1,3-dihydro-3-oxo-2H-indol- 2-ylidene)-2,3-dihydro-3-oxo-1 H-indole-5-sulfonic acid. Additionally, FD&C Blue No. 2 is obtained by heating indigo (or indigo paste) in the presence of sulfuric acid. The color additive is isolated and subjected to purification procedures. The indigo (or indigo paste) used above is manufactured by the fusion of N-phenylglycine (prepared from aniline and formaldehyde) in a molten mixture of sodamide and sodium and potassium hydroxides under ammonia pressure. The indigo is isolated and subjected to purification procedures prior to sulfonation.
The largest study suggested, but did not prove, that this dye caused brain tumors in male mice. The FDA concluded that there is "reasonable certainty of no harm", but personally I'd rather avoid this ingredient and err on the side of caution.
Red 40 (artificial color)
The color additive FD&C Red No. 40 is principally the disodium salt of 6-hydroxy-5-[(2-methoxy-5-meth yl-4-sulfophenyl)azo]-2-naphth alenesulfonic acid.
The most widely used food dye. While this is one of the most-tested food dyes, the key mouse tests were flawed and inconclusive. An FDA review committee acknowledged problems, but said evidence of harm was not "consistent" or "substantial." Like other dyes, Red 40 is used mainly in junk foods. Personally I'd rather avoid this ingredient and err on the side of caution.
A white powder, TiO2, used as an exceptionally opaque white pigment and dough conditioner.
Non toxic but an unnecessary ingredient that could just as well be left out.
Yellow 5 (artificial color)
The color additive FD&C Yellow No. 5 is principally the trisodium salt of 4,5-dihydro-5-oxo-1-(4-sulfoph enyl)-4- [4-sulfophenyl-azo]-1H-pyrazol e-3-carboxylic acid (CAS Reg. No. 1934-21- 0). To manufacture the additive, 4-amino-benzenesulfonic acid is diazotized using hydrochloric acid and sodium nitrite. The diazo compound is coupled with 4,5-dihydro-5-oxo-1-(4-sulfoph enyl)-1H-pyrazole-3-carboxylic acid or with the methyl ester, the ethyl ester, or a salt of this carboxylic acid. The resulting dye is purified and isolated as the sodium salt.
The second most widely used coloring can cause mild allergic reactions, primarily in aspirin-sensitive persons.
Yellow 6 (artificial color)
The color additive FD&C Yellow No. 6 is principally the disodium salt of 6-hydroxy-5-[(4-sulfophenyl)az o]-2-naphthalenesulfonic acid (CAS Reg. No. 2783-94-0). The trisodium salt of 3-hydroxy-4-[(4- sulfophenyl)azo]-2,7-naphthale nedisulfonic acid may be added in small amounts. The color additive is manufactured by diazotizing 4-aminobenzenesulfonic acid using hydrochloric acid and sodium nitrite or sulfuric acid and sodium nitrite. The diazo compound is coupled with 6-hydroxy-2-naphthalene-sulfon ic acid. The dye is isolated as the sodium salt and dried. The trisodium salt of 3-hydroxy-4-[(4-sulfophenyl)az o]-2,7-naphthalenedisulfonic acid which may be blended with the principal color is prepared in the same manner except the diazo benzenesulfonic acid is coupled with 3-hydroxy-2,7-naphthalenedisul fonic acid.
Industry-sponsored animal tests indicated that this dye, the third most widely used, causes tumors of the adrenal gland and kidney. In addition, small amounts of several carcinogens contaminate Yellow 6. However, the FDA reviewed those data and found reasons to conclude that Yellow 6 does not pose a significant cancer risk to humans. Yellow 6 may also cause occasional allergic reactions. Another ingredient I would rather avoid and err on the side of caution rather than risking my pet's health.