What to Know About the Apple That Doesn't Turn Brown

— -- Apples are so old school that they're Old Testament, but the U.S. Department of Agriculture just approved a newfangled apple with a genetically modified twist: It doesn't turn brown when exposed to air.

The USDA approval allows trees bearing the new fruit to be sold to farmers, but safety approval by the Food and Drug Administration for consumption can't be far behind, according to Patty Lovera, assistant director of Food and Water Watch, a consumer-rights group based in Washington, D.C. She said it will probably still be a few years before they're sold in stores.

"The USDA is usually the big step, and that happened today," Lovera told ABC News, explaining that GMOs -- or genetically modified organisms -- are already on the market with corn, soy and other crops designed to fend off insects or survive being sprayed down with weed-killers. "This is kind of the next generation, where they're trying to promote a consumer benefit. When you cut it, it won't turn brown."

The scientists behind the so-called Arctic apples "turned off" the gene found in apples that caused them to turn brown -- a process that differs from other GMO crops and foods, which usually add genes from other organisms. For instance, the GMO salmon from AquaBounty Technologies is an Atlantic salmon with an added Pacific salmon gene to make it grow faster and an added eel gene to make it grow year-round.

"This time, they're going into the existing material and turning off genes, but what else did that gene do that they turned off?" Lovera asked, pointing to the concerns that some people have about the potential unintended consequences of manipulating genes.

For example, if that gene helped protect the apple from pests, and it's no longer "on," farmers could need more pesticides, she said. Her other concern, she said, is that now consumers won't know how long apples have been sitting out.

Dietitian Amy Jamieson-Petonic, of University Hospitals Case Medical Center in Cleveland, Ohio, said research suggests genetically modified foods don't pose an immediate threat to people's health. But there's always room for more research, she said.

Apples that have turned brown, or oxidized, aren't nutritionally different from apples that have not yet turned brown, she said, but she recommends eating apples before that happens. If you don't want apples to turn brown, squeeze a little lemon juice on them, she said. The vitamin C keeps the fruit from oxidizing.

Okanagan Specialty Fruits, which makes the Arctic apples, said in a statement that it was excited by the USDA approval and it is "working hard to get as many trees in the ground as possible so that you’ll be able to purchase Arctic apples in stores within the next few years."

"The supply-chain can feel confident knowing that Arctic apples are likely the most tested apples in existence," the company said. "Rigorously reviewed by multiple regulatory bodies, all evaluations reach the same conclusion -- Arctic apples present no unique risks and are just as safe and healthful as any other apple."