Apples That Don’t Turn Brown: What’s Keeping Them off the Shelves?

Author:  Michael Nagle
Institution:  American University
Date:  October, 2012


Most Americans eat genetically modified (GM) food every day. Regulatory agencies do not require them to be labeled, since each crop is determined to be nutritionally equivalent to organic food. This may soon change in California, where Proposition 37 will reach the ballots in November. The bill, titled the California Right to Know Genetically Modified Food Act, is the first of its kind in the U.S.

Many vegetables, including most corn and soybeans, are genetically modified for pest resistance and increased yields. The first GM fruit, an apple that does not turn brown when cut, is now pending Department of Agriculture approval. A slow-to-brown apple developed by the University of Minnesota via traditional crossbreeding is already on the market. The only significant differences between the apples are that the non-GM one still turns brown, even if more slowly than most apples, and it took decades longer to develop.

Apples turn brown due to an enzyme reacting with oxygen in the air. The makers of the GM Arctic Apple, named as such because it stays white, disabled the four genes that produce that enzyme. Genetic modification often involves taking genes from one organism and moving them to another, but they went with the more simple method of silencing genes within one organism.

According to Neal Carter, president of Okanagan Specialty Fruits, the developer of the GM apple, crossbreeding can’t be as effective in making a slow-browning apple because four different genes control browning. “Looking for parents for  a breeding program with all four of these genes at low levels would be difficult.”

University of Minnesota’s crossbreeding team did not seek out the genes that control enzymatic browning. Making a slow browning apple was not their goal, according to David Bedford, who works on the program. They discovered accidentally that the apples were slow to brown when they were left out overnight. They were named Snow Sweet because of how long they stay white.

“To us it’s very much a secondary issue,” Bedford said. “We would never say, this is why you should buy the Snow Sweet apple. We tell you two or three things before that... and oh, by the way, it’s very slow to brown... Let’s just say that we weren’t very excited about that characteristic.” Working toward a slower-to-brown apple would risk taste and growth habits, so they didn’t pursue it.

The Arctic Apple was made from an existing cultivar, or variety of apple, and is nutritionally equivalent to other apples, including Snow Sweet. The apple is not transgenic, meaning it does not have genes from other species. Rather, Carter and his team just silenced the genes that code for the enzyme that causes browning.

The apple is currently pending USDA approval. Last November, the USDA stated that they would try to cut the average approval time for GM crops from 3 years to 18 months. Despite the lengthy approval process, the apple is more welcome in the US than it would be in Europe.

All products with more than 0.9% GM ingredients must be labeled in the European Union. In six European nations, GM food is banned entirely. Developers of GM products, including Luke Alphey, Ph.D, who developed sterile mosquitoes to fight Dengue fever, say the American approach is “conceptually the better way to go.” Existing legislation that deals with products on a case by case basis is sufficient, he said. There were no laws in the states about GM insects, as laws only cover livestock and plants, but the FDA stepped up to regulate the mosquitos. The Mosquito Control Board in Key West, Florida will buy the mosquitos if and when they are approved by the FDA.

If California passes Prop 37, companies will likely use the new labelling nationwide, rather than print two different sets. The law may disproportionately affect small farmers who will need to individually label corncobs and tomatoes and do not currently have assembly lines to do so.

“We believe that the benefits of ensuring a consumer's right to know outweighs any minor inconvenience for the grower of those GE apples,” said Kari Hamerschlag with Environmental Working Group. Although “encouraged” by the fact the Arctic Apple will be labelled voluntarily, the group supports the bill because, “most producers of GE foods are vehemently opposed to letting their consumers know what is in their food.”

“We’re not against the labeling and we do plan on labeling our apples,” Carter said. “The labeling of a fruit is a lot more complicated than people think. There’s a limited amount of space, and what about if  only 1 or 2 percent of the product is genetically modified?”

To pass the USDA’s approval process, a GM product must be determined to be nutritionally equivalent to its organic ancestor, in addition to being safe. In response to Prop 37, the American Medical Association released a statement saying, “There is no scientific justification for special labeling of bioengineered foods ... Consumers wishing to choose foods without bioengineered ingredients may do so by purchasing those that are labeled USDA Organic." They are accompanied by the National Academy of Sciences and World Health Organization. 

This science feature article was written under the guidance of JYI Science Writing Mentor Brooke Borel.