Salmon as food

Salmon is a common food fish classified as an oily fish with a rich content of protein and omega-3 fatty acids. Norway is a major producer of farmed and wild salmon, accounting for more than 50% of global salmon production. Farmed and wild salmon differ only slightly in terms of food quality and safety, with farmed salmon having lower content of environmental contaminants, and wild salmon having higher content of omega-3 fatty acids. Salmon flesh is generally orange to red, although there are some examples of white-fleshed wild salmon. The natural color of salmon results from carotenoid pigments, largely astaxanthin and canthaxanthin in the flesh. Wild salmon get these carotenoids from eating krill and other tiny shellfish. The concentration of carotenoids (mainly canthaxanthin and astaxanthin) exceeds 8 mg/kg of flesh, and all fish producers try to reach a level that represents a value of 16 on the "Roche Colour Card", a colour card used to show how pink the fish will appear at specific doses. This scale is specific for measuring the pink colour due to astaxanthin and is not for the orange hue obtained with canthaxanthin. The development of processing and storage operations, which can be detrimental on canthaxanthin flesh concentration, has led to an increased quantity of pigments added to the diet to compensate for the degrading effects of the processing. In wild fish, carotenoid levels of up to 25 mg are present, but levels of canthaxanthin are, in contrast, minor. Raw wild salmon is 70% water, 20% protein, 6% fat, and contains no carbohydrates (table). In a 100 gram reference amount, raw salmon supplies 142 calories, and is a rich source (20% or more of the Daily Value, DV) of several B vitamins, especially vitamin B12 at 133% DV, selenium (52% DV), and phosphorus (29% DV). Dietary minerals in moderate content are copper (15% DV) and potassium (10% DV). PCBs, metformin, and mercury are some of the pollutants found in wild salmon, caught close to wastewater treatment plants of major metropolitan areas in the United States’ Pacific Northwest.