Costco will not put genetically modified salmon on its shelves. “Although the Food and Drug Administration has approved the sale of GM salmon, Costco has not sold and does not intend to sell GM salmon at this time,” the Issaquah-based company said in a statement. The FDA gave its blessing to genetically modified salmon last week, saying there is “no biologically relevant difference in the nutritional profile of (modified) salmon compared to that of other farm-raised Atlantic salmon.