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Do Processed Foods Contain GMOs?

A controversial GMO labeling bill signed into law by the president has raised interesting scientific and regulatory questions: Do foods processed from genetically modified organisms, like refined sugar and soybean oil, contain genetic material? If not, would they be labeled as GMOs?

The law’s definition of “bioengineering” is at the crux of the debate. It states that foods must “contain genetic material that has been modified” in order to be labeled.

SciCHECKsquare_4-e1430162915812The Food and Drug Administration and some opponents of the law have claimed many refined foods would most likely not be subject to labeling because, they argue, the genetic material has been removed through processing. As we’ll explain, this isn’t completely true.

The U.S. Department of Agriculture and proponents of the legislation, on the other hand, have claimed the USDA does have authority to label highly refined oils, sugars and high fructose corn syrup produced from GMOs.

The law gives the USDA, not the FDA, regulatory power over the matter. Still, it’s unclear how exactly the USDA would implement the regulation. For example, some processed foods may contain modified genetic material, but current techniques might not be able to detect that material reliably. Would these foods, then, be subject to labeling?

We took a look at what the scientific literature has to say on the matter. In short, scientists have detected modified genetic material in some processed foods — but not others. Whether or not processed foods contain detectable genetic material depends on the food processing and detection methods used.

We’ll go over the debate that took place in Congress on the legislation’s definition of “bioengineering.” We’ll also explain how and why processing techniques degrade, but don’t necessarily remove, the genetic material in foods.

A Narrow Definition?

On July 6, the Senate passed a bill to establish a mandatory national standard for labeling food containing genetically modified organisms. On July 14, the legislation also passed in the House. Signed by the president on July 29, the law gives the USDA authority to require food manufacturers to label their products that contain GMOs.

Labels can come in three forms — on-package text, a USDA-designed symbol, or a smartphone- or scanner-readable code that brings consumers to a website with relevant information. Small businesses can also elect to use an on-package phone number or website.

During floor addresses and a press conference on July 6, multiple senators took issue with the legislation’s definition of the term “bioengineering.” For example, they argued it would exclude widely used products like soybean oil, high fructose corn syrup and refined sugar made from GMOs.

The bill defines “bioengineering” as referring to a food “that contains genetic material that has been modified through in vitro recombinant deoxyribonucleic acid (DNA) techniques; and … for which the modification could not otherwise be obtained through conventional breeding or found in nature.”

Among other sources, the senators cited information provided by the Food and Drug Administration. In a technical assistance document for Congress, the FDA stated the phrase “that contains genetic material” in the legislation’s definition of “bioengineering” would “likely mean that many foods from GE sources will not be subject to this bill.” It added, “oil made from GE soy would not have any genetic material in it. Likewise, starches and purified proteins would not be covered.”

During a floor address on July 6, Sen. Jeff Merkley, a Democrat from Oregon, said the phrase “contains genetic material that has been modified” was “magic language” that “transforms a GMO ingredient to a non-GMO ingredient.” He added, “when you make high-fructose corn syrup, when you make sugar for sugar beets, when you make soybeans oil from soybeans, that information is stripped out.” At a press conference on the same day, he cited the FDA when making a similar claim.

Montana Sen. Jon Tester and California Sen. Barbara Boxer, both Democrats, made similar claims during floors addresses on July 6. In addition, during a floor address on July 14, Rep. Tulsi Gabbard, a House Democrat from Hawaii, said, “This bill has raised concerns from the FDA over the bill’s narrow definition of genetic engineering that leaves common foods without any labeling requirement at all.”

In contrast, Sen. Debbie Stabenow, a Democrat from Michigan who wrote the bill with Kansas Republican Sen. Pat Roberts, claimed that their “bill provides authority to the USDA to label refined sugars and other processed products.”

According to the USDA itself, Stabenow is correct. In an email to us, a spokesperson told us the USDA does believe it has authority to label products that contain highly refined oils, sugars and high fructose corn syrup as containing GMOs.

But we don’t yet know how exactly the USDA will decide which foods require labels and which don’t. The spokesperson told us “a working group has already been established to begin the important work of crafting rules to properly and promptly implement the new law.”

Quality, Not Quantity

Many food processing techniques, like milling, heating and fermentation, degrade, but don’t necessarily remove, the genetic material in foods. This means processed foods may still contain genetic material, or DNA, from GMOs, but scientists might not be able to detect it with current techniques.

Why? DNA, or deoxyribonucleic acid, normally comes in the form of two long strands of molecules called nucleotides (i.e. the double helix). The strands and the nucleotides that make them up are linked together by bonds between hydrogen and other atoms. Heat and other processes degrade the DNA in foods by breaking these bonds, effectively chopping the DNA into short segments. When these segments are too short, the DNA can’t be detected with currently available techniques.

On the other hand, scientists can more easily detect DNA in raw food products, like fresh vegetables and fruits, because the DNA remains relatively intact. Still, time (i.e. decomposition) also leads to DNA degradation, which is why obtaining high quality DNA samples from older crime scenes can prove more difficult. It’s also why obtaining DNA from dinosaur bones is highly unlikely.

Multiple papers we came across on the subject voiced the need to both standardize and improve detection methods, as tracking GMOs in foods is also important to the implementation of GMO labeling laws in other countries.

The European Union, for example, requires labels on foods that contain more than 0.9 percent of GM material. Anything under that quantity does not require a label. But in order to know how much modified genetic material a food contains, researchers have to detect it first. Improving methods might entail finding ways to detect shorter segments of DNA in processed foods or obtaining purer samples in the first place.

In short, it’s often more a matter of DNA quality, not quantity, when it comes to whether some processed foods contain genetic material that can be detected.

DNA in Processed Foods

So, in which processed foods have scientists detected DNA from GMOs?

Contrary to the FDA’s claims, researchers have detected DNA from GMOs in fully refined soybean oil. Isabel Mafra, a food science specialist at the University of Porto in Portugal, and others published a study in 2010 in the journal Food Research International that did exactly that.

The authors specifically looked at soybean oil made from Roundup Ready soybeans. Roundup Ready soybeans were genetically modified by scientists at the agricultural corporation Monsanto for resistance to the herbicide glyphosate. This means farmers can spray their crops with glyphosate and the crops will be able to withstand that application.

As we’ve already explained in a previous article, Roundup Ready soybeans themselves would fall under the bill’s definition of bioengineered: They were created in a lab using recombinant DNA technology by inserting foreign DNA from a bacteria species into the genome of soybeans. Monsanto also makes Roundup Ready corn, among other crops, using similar methods.

But what about soybean oil made from these GM soybeans? According to Mafra and colleagues, it’s possible to not only detect, but also quantify DNA from GMO soybeans in fully refined soybean oil.

When we contacted Merkley’s office to ask for support for his claims, his deputy communications director, Martina McLennan, pointed us to a 1998 paper published in the journal European Food Research & Technology that states “no genetic material can be recovered after the first processing steps of soybean oil, i.e. when crude soybean oil is simply centrifuged.”

But as we’ve explained, researchers did detect DNA in fully refined soybean oil in 2010.

Gao Xuejun and other experts at the Northeast Agricultural University in China have also detected DNA from GMOs in soy lecithin, corn starch and other processed foods from GM soybeans, corn (i.e. maize) and rice. Soy lecithin is an emulsifying and stabilizing agent added to many foods. China is also among the nations that do have GMO labeling laws.

Published in the journal Food Control in 2011, Xuejun and colleagues’ paper concludes that their detection technique “is appropriate for qualitative detection of transgenic [GM] soybean, maize and rice in highly processed products except for refined oil.”

Xuejun and colleagues state their “main limitation” for detecting DNA in refined oils, including soybean oil, was the “quality of DNA obtained” from samples. They added that the “standardization of extraction methods to obtain pure enough DNA from refined oil is one of the main challenges to fulfill [GMO] regulation requirements” globally.

To reiterate, this doesn’t mean these processed foods don’t contain DNA from GMOs, but scientists have trouble detecting the DNA because it has degraded.

But other food processing techniques do appear to completely strip the DNA out of foods.

Sugar refined from sugar beets, for example, doesn’t contain DNA. Back in 1998, researchers at the University of Stuttgart in Germany found that the DNA from GM sugar beets was removed during the purification process of making sugar. Ralf Mattes, a geneticist, and others concluded in a Journal of Biotechnology paper that “sugar obtained from conventional and transgenic beets is indistinguishable or substantially equivalent with respect to purity.”

In 2009, Satoshi Furui and others conducted a similar analysis and, again, couldn’t detect DNA in refined sugar from GM sugar beets. Published in the journal Food Hygiene and Safety Science, the study led to the Japanese government’s decision to not require mandatory GMO labels for sugar products.

As for high fructose corn syrup, McLennan, from Merkley’s office, pointed us to an Oct. 7, 2014, Q&A from gmoanswers.com. In an answer to the question, “Does High Fructose Corn Syrup contain GMOs?,” a representative from the Corn Refiners Association wrote, “the genetically modified DNA or protein is degraded during the process that breaks corn down into HFCS, which makes the genetically modified DNA or protein undetectable.”

First off, we weren’t able to independently verify this claim with our own review of the scientific literature. Second, regardless, this Q&A doesn’t support Merkley’s claim that the genetic “information” in high fructose corn syrup has been “stripped out” completely. It may still be present, but the DNA has degraded to undetectable levels, according to the Corn Refiners Association.

At this point, we can’t comment on whether or not certain processed foods will ultimately be exempted by the USDA from requiring a GMO label. We also don’t know what the future may hold in terms of litigation over the matter. But we can say members on both sides of the debate have made valid — and invalid — points. Refined sugar doesn’t contain DNA based on current detection methods, but soybean oil, soy lecithin and corn starch do. The genetic contents of high fructose corn syrup remain unclear.

Editor’s Note: SciCheck is made possible by a grant from the Stanton Foundation.