Ever consider the color tricks food manufacturers use to get you to buy their foods?
A Life Filled With Colour ran into this issue with a bag of potatoes. Opposite hues on the color wheel basically cancel each other out, creating a neutral color. Wrapped, unripe, green potatoes in pink plastic bags essentially look brown through the plastic...until you get home and realize you've been tricked.
The industry says the research suggests that people may be willing to pay a higher price for a salmon of the 'right' hue.(source)
FYI, the Monterey Bay Aquarium offers a handy free pocket-sized guide on purchasing seafood.
DSM Yolk colour fan deck, for "reliable measurement of reproducible yolk colour"
After determining the desired yolk color, manufacturers feed birds the required amount of a nutritional supplement, and voila, lovely yellow pigment.
I feel so manipulated!