While reporting my story on how foods earn a label certifying them as "non-GMO," I came across a comment that struck me – and it might surprise you, too.

The comment came from Ken Ross, the CEO of Global ID. (He didn't make it into the final story.) Global ID is the parent company of FoodChain ID, one of the companies that traces ingredients to determine whether they contain genetically modified organisms (GMOs).

I was surprised when Ross explained that genetic testing is only a small part of the work that goes into certifying a product as "Non-GMO." Partly, that's because often a little investigative work can reveal that an item couldn't possibly contain a GMO, and that makes expensive and laborious genetic testing unnecessary. But it's also because sometimes a genetic test wouldn't reveal the GMO anyway. Ross says processing often degrades an ingredient to the point of making its DNA – or anything else that's genetically modified, like proteins — undetectable.

"A lot of oils would be an example of that," Ross says — for instance, vegetable oils made from GMO soybeans or canola. Or take sugar made from GMO sugar beets. These ingredients are highly processed before you get to the finished product, by which time, "there's no DNA left," he says.

Ross says that raises an interesting question around why consumers want to know about GMO ingredients.

"If they're concerned from a health and safety point of view," he says, "then if there's no more DNA left, should they still be concerned?"

That's a question you don't hear often. Of course, Ross acknowledges that some consumers aren't worried about the health consequences of GMOs but have other reasons to want to avoid buying products that include them.

"They could have concern about environmental impact," he says. "So whether or not there was still [genetically modified ingredients] in the food product, they might not want to support the use of [genetic modification] as a technology."

Or, they might avoid GMOs for political reasons, he says, because they object to the fact "that large companies are dominating the economic landscape and controlling the intellectual property around seeds."

In the U.S., genetically engineered plants and animals are regulated by the Food and Drug Administration and the Environmental Protection Agency on a case-by-case basis. The agencies say that genetically engineered crops must meet the same safety standards applied to conventional crops.

Despite much attention around labeling GMOs, many consumers remain confused about what GMOs are and whether they should care about them, something comedian Jimmy Kimmel has had fun with.

The absence of understanding, though, much like the absence of DNA, doesn't seem to have much impact on people's passion. As long as opponents are willing to pay for products labeled as non-GMO, the business niche that has grown up to meet the demand will continue to thrive.

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