In commenting on the ethics of sophisticating foods a well-known American agricultural chemist was wont to remark that although the addition of carrot color to butter is manifestly wrong, yet when carrots are fed in order to improve the color of the milk fat the viewpoint is altered; for this now involves adulteration with the connivance of the cow. A similar complication may arise in connection with new experiments by Dr. Oscar Riddle.
Bearing in mind the familiar fact that certain substances which are not readily oxidized or destroyed in the body may reappear in the secretions, such as milk, and in the eggs of animals, he has attempted to ascertain whether compounds exhibiting a preservative action are eliminated in this manner. Physiologically this question is of interest in relation to the permeability of the ovarian egg-membranes and the passage of substances from the blood through both follicular and vitelline membranes. The transportation of the fat-soluble dye Sudan III into the yolk of the hen's egg can easily be demonstrated, the coloring-matter appearing as rings of pink in a cross-section of the egg of a hen which has received the dye. Such pigments, insoluble in water, travel dissolved in fat in the organism, being deposited with it in characteristic locations such as adipose tissue or egg yolk, or being excreted with the fat of milk or dissolved in the special solvents of the bile.1 In other words, compounds which are comparatively inert and not destroyed in the body may tend to find a suitable solvent and thus travel from place to place until eliminated in some way.
UNIQUE FOOD PRESERVATION. JAMA. 2012;307(6):545. doi:10.1001/jama.2012.35