Scientists have created a genetically modified milk that lacks a key protein involved in triggering allergies — an impressive technical feat that won plaudits in the biotechnology world.

But the development, published Monday in the journal Proceedings of the National Academy of Sciences, isn’t likely to lead soon to less-allergenic milk. The process for getting government approval to sell food derived from genetically engineered animals appears to be a hopeless logjam.

A salmon with designer DNA has been in regulatory limbo since the Food and Drug Administration concluded that the fish appeared to be safe and without environmental risk two years ago. The company behind the fish, AquaBounty Technologies, is still waiting for the final regulatory steps and a sign-off from the FDA.

A herd of so-called enviropigs engineered to digest plant phosphorus more efficiently — cutting feed costs as well as levels of polluting phosphorus in their manure — was euthanized this year because of funding difficulties and public wariness about genetically modified organisms. Cell and semen samples have been banked in cold storage until the regulatory climate and societal attitudes improve, according to the Canadian scientist who was in charge of the project.

Goats that produce a protein in their milk that can help fight diarrhea in young children are being moved from California to Brazil for commercial development in what some scientists see as a more biotechnology-friendly locale.

Scientists are working on a range of products in various stages of development, including virus-resistant chickens, meat with healthier fat and mastitis-resistant dairy cows that would require fewer antibiotics.

But the slow pace of progress on AquaBounty’s application has had a chilling effect on animal biotech efforts — which are conducted in academic laboratories and small companies, not by the multinational corporations that develop genetically modified plants. Efforts have been foundering for lack of funding, or moving overseas.

AquaBounty Technologies has enough money to survive until the end of January, said Ronald Stotish, president and chief executive of the company, based in Maynard, Mass.

In frustration, more than 50 scientists and biotechnology leaders sent a letter to President Obama last month asking him to urge the FDA to move forward on the AquaBounty salmon decision.

“There is much more at stake here than just a fish,” the scientists wrote.

UC Davis animal geneticist James Murray was one of those who signed the letter. He has engineered goats to produce the human protein lysozyme in their milk, which helps shape the bacterial flora in the gut and improve gastrointestinal health. Should his goats or someone else’s transgenic animals come before the FDA, “we need them to make a decision,” he said. “We need the political process to allow the science-based regulatory process to work.”

Murray said he had arranged to move his transgenic goats to Brazil for development there because he saw no opportunity for regulatory approval or funding in the United States in the near future.

The new study on hypoallergenic cow milk was conducted at AgResearch in Hamilton, New Zealand, a government-owned research institution. Scientists genetically engineered cow cells to suppress the gene for a protein in whey — called beta-lactoglobulin, or BLG — that is present in cow milk but not in human milk.

Beyond creating milk that was less likely to cause allergies, the scientists wanted to understand the function of BLG in milk, an extremely complicated fluid packed with proteins, fats and sugars.

To remove the protein, the scientists engineered cow cells to make tiny RNA molecules that would interfere with the activity of the BLG gene, effectively silencing it. Then they used cloning technology to create a female calf from the genetically modified cells. Analysis of a small amount of milk obtained from the calf through hormonal induction found no traces of BLG.

For reasons the scientists do not understand, the milk contains elevated levels of a group of other proteins called casein, which also can trigger an allergic reaction. But that could be helpful for cheese-making, they said.

The calf is now about 11 months old, and the scientists intend to breed it next year so they can analyze the milk more extensively, said study coauthor Stefan Wagner, an animal geneticist at AgResearch. Among other things, they plan to see how it differs from conventional cow milk and test its allergy-reducing potential in mice, he said.

Dr. Robert Wood, director of pediatric allergy and immunology at Johns Hopkins Children’s Center in Baltimore, said he doubted the milk in the study would help his patients. Though it’s true that many children can’t tolerate BLG, they usually are allergic to a variety of milk proteins, including casein. The higher casein therefore presents “probably the worst-case scenario for most of our patients,” he said.

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.

rosie.mestel@latimes.com