andrew schneider investigates

March 10, 2008

Chemical colorings and farmed salmon

Filed under: Environmental health issues,FDA,Food additives,Food labeling,Salmon,Seafood — Andrew Schneider @ 10:00

Farm-raised salmon are being fed more like a cow than like a fish, at least according to Joe Schwarcz, who is the director of McGill University’s Office for Science and Society.

Schwarcz is also a columnist for the Montreal Gazette and this week he pondered the chemical feed and coloring routinely added to make the gray-fleshed, captive fish look more like their brightly hued, robust, wild kin from the Pacific.

The coloring agent is astaxanthin, a naturally occurring pigment found in a variety of algae that serve as food for krill, shrimp and crayfish, favorite food of the ocean-cruising salmon and the source of the fish’s rich orange color.

Salmon labeled as farm-raised

But, Schwarcz reports that these days, however, most salmon are raised on fish farms. where they are fed pellets made from other fish. The feed lacks astaxanthin, so the salmon ranchers add it to the feed.

The commercial production of astaxanthin is a huge industry, relying on
three distinct processes, he writes. Fermentation of sugar by certain yeasts can
produce the compound, as can extraction from specially grown algae. But
the most economical, and therefore the most common process, relies on a
14-step chemical synthesis from raw materials sourced from petroleum. Actually, the name astaxanthin refers to any one of three very closely related compounds with very subtle differences in molecular structure.

Check out the professor’s report for more on the raising of this cash crop.


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