CORRECTION: This story was updated on March 25, 2015, to reflect that these are not the first foods engineered through gene silencing that have gotten FDA approval.

The Food & Drug Administration has cleared the way for two genetically modified crops to hit the U.S. market—apples that resist browning and potatoes that produce less of the carcinogen acrylamide at high temperatures. The agency declared on March 20 that the crops are just as nutritious and safe as conventional apples and potatoes.

[+]Enlarge Credit: Okanagan Specialty Fruits [+]Enlarge Credit: Shutterstock

The crops are controversial because they rely on a process called gene silencing or RNA interference (RNAi). Although there is no evidence to suggest the products will pose a health or safety risk to humans or the environment, some consumer advocacy groups are raising concerns about the approval process.

The modified apples were developed by Canadian-based Okanagan Specialty Fruits under the name Arctic apples. This fruit contains added apple genes that code for an enzyme, polyphenol oxidase (PPO), that causes apple flesh to turn brown. The extra genes trigger RNAi, which inhibits expression of all genes that produce PPO.

In Innate potatoes, developed by Idaho-based J.R. Simplot, gene silencing reduces the amount of the amino acid asparagine as well as amounts of reducing sugars formed in the spuds. At high temperatures, such as those used in frying, asparagine reacts with reducing sugars to form acrylamide. That chemical has been shown to be carcinogenic in animal studies. In addition, RNAi lowers the amount of PPO enzymes in the potatoes that lead to the formation of black spot bruises.

FDA’s approval of the two crops spurred a coalition of advocacy groups to send letters to fast-food restaurants, urging them not to sell the modified apples and potatoes. The coalition warns of potential environmental, health, and economic risks associated with the products. They also raise concerns that the products won’t be labeled as containing genetically modified organisms (GMOs), saying that consumers have the right to know whether they are eating GMOs.

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Public confidence in GMO products is low because the GMO approval process “is badly flawed,” says Gregory Jaffe, biotechnology director at the Center for Science in the Public Interest. For the newly approved apple and potato, FDA evaluated data produced by the companies and encouraged voluntary consultations between the businesses and the agency.