The group are Xanthophylls, (from the Greek, Xanthos - yellow) although is more orange than yellow, and are related to carotene. Extracted using the solvent hexane they normally contain other source plant material. Canthaxanthin is also available in some mushrooms, crustaceans and fish, so vegetarians beware, but it is normally obtained commercially from beta-carotene. As well as being used in such products as chicken in breadcrumbs, fish fingers, mallow biscuits, pickles and preserves, sauces and sweets it is also fed to farmed salmon and trout to enhance the colour of the flesh. Fed to laying hens to make to colour egg yolks. It is also used to colour the skin in artificial sun-tan products where its' use has given concern to eyesight problems. In particular a deterioration in twilight vision, delays in adapting to the dark and sensitivity to glare. These products use greater quantities than those used in food, although at present there is no direct correlation, but with the increasing use of Canthaxanthin as a 'natural' substance in food, there is a real cause for concern.