Factory-farmed salmon meat is usually a little grey, and looks rather unappetising when one is used to healthy wild pink. Swiss chemical firm Hoffman-Laroche has the answer, a range of pinks to suit all requirements, displayed like a paint swatch and applied to the animals through their food. They offer chicken farmers the same service, using the same artificial colourings, to make their egg yolks the desired shade of yellow.

One of the chemical dyes added to the feed is cathaxanthin (E161g), which was:

• banned in the 1980s from 'sun-tan pills' due to concerns about temporary blind spots and damage to the retina
• banned from processed foods (such as pickles)

Major salmon farm company Scottish Quality Salmon commented, "Most of what is done is for either fish health and welfare reasons or consumer demand ..."