Even if the milk were further modified, the regulatory barriers and societal discomfort may present bigger challenges.
Though the public routinely consumes processed foods made with genetically modified corn and soybeans, the idea of eating products from transgenic animals will be tougher for consumers to accept, said Gregory Jaffe, director of the biotechnology project of the Washington-based Center for Science in the Public Interest.
"People feel different about eating animals than they do about crops, and when you're talking about cows and milk — milk is something we give our children," said Jaffe, who was on an advisory committee that reviewed safety data for the AquaBounty salmon in 2010 and saw no cause for alarm based on the data he reviewed then.
Indeed, many animal geneticists said they suspected the regulatory stalling on the AquaBounty case had more to do with politics than an inefficient or overly fastidious FDA.
Politicians have repeatedly attempted to block approval of the genetically modified salmon, they noted. Some scientists say they suspect the roadblock is higher up in the Department of Health and Human Services or even the White House.
"We believe that the FDA has done its thing and that they believe the product is approvable, and that the process has been corrupted by political interference beyond the FDA," said Stotish, the AquaBounty chief executive.
FDA spokeswoman Morgan Liscinsky said in an email that the company's "application is still pending, and we do not have any information on a timeline." An environmental assessment is being conducted, she said.
The only FDA-approved transgenic animal product is an anti-clotting drug called ATryn, which is extracted from the milk of genetically modified goats. The drug, made by GTC Biotherapeutics Inc. of Framingham, Mass., is selling well, and the company plans to develop other lines of goats and rabbits to make milk-based drugs for patients with hemophilia, autoimmune diseases and cancers, GTC President Yann Echelard said.