Mandatory labeling for genetically modified food suffered two more setbacks in this past election as Colorado and Oregon voters rejected ballot measures that would have required GMO labels to appear on lab-altered goods.

While Maui County in Hawaii passed a temporary ban on cultivating genetically modified crops, directly affecting the operations of Monsanto (NYSE:MON) and Dow Chemical's (NYSE:DOW) AgroSciences division, legal challenges may still tie up the ordinance's implementation.

Soy Lettuces

The soy and lettuce field at Ag Park at Kunia on Oahu that Monsanto helped bring together. Source: Monsanto Hawaii.

Genetic engineering of food remains a hot-button topic, but here are 11 things you should know about GMOs.

1. What are GMOs?
Genetically modified organisms are organism whose genetic makeup has been altered at the molecular level through laboratory processes that use DNA taken from bacteria, viruses, or other plants and animals, and inserted into other organisms to obtain desired traits.

2. The overwhelming majority of Americans support labeling laws.
Numerous public opinion surveys found the vast majority of Americans want genetically modified food labeled. The New York Times, The Washington Post, ABC News, and more all found 90% or more of those surveyed were in favor of fully labeling GMOs.

3. 64 countries already require genetically modified food be labeled.
Although it's portrayed as some weird development in the U.S., most of the developed world -- including the all of the European Union, Japan, Brazil, Australia, New Zealand, South Korea, Russia, and China -- have mandatory labeling of genetically modified foods. Here in the U.S., where Monsanto, Dow, and DuPont (NYSE:DD) dominate the market,attempts to force labeling are being thwarted.

4. The U.S. is the world's leading producer of genetically modified foods
In 2012, the United States accounted for 69.5 million of the 170.3 million hectares of biotech crops globally, over 40% of the total. 

5. You're likely already eating GM foods and have been doing so for decades.
At least 85% of all soybeans, corn, sugar beets, and canola is grown from GMO seeds, and most of those are made by Monsanto. If you're eating something that has those listed as ingredients on the label, there's a good chance it's been modified on a genetic level. It's estimated 60% to 70% of all food on supermarket shelves is genetically modified.

Images

Corn is the biggest crop grown in the U.S. and almost all of it -- 88% -- is GMO. Photo: Flickr via Rosana Prada.

And if you're eating something with high fructose corn syrup, there's a 90% chance you're consuming GMOs. Further, 95% of food-producing animals in the U.S. are fed genetically engineered ingredients. 

6. Three states in the U.S. have passed mandatory labeling laws
Vermont, Connecticut, and Massachusetts have all passed mandatory labeling laws, but the latter two require other states to pass laws before theirs kick in, and Vermont's is being challenged in court, delaying its implementation.

7. Food retailers are starting to take matters into their own hands
Whole Foods Market (NASDAQ:WFM) announced it would require its suppliers to identify genetically modified foods on their labels by 2018, while Chipotle Mexican Grill (NYSE:CMG) became the first national fast-food chain to disclose which ingredients are genetically engineered. Trader Joe's now makes its private-label foods GMO-free. 

8. GMO crops do offer benefits
Fields are generally more productive using GMO seeds, and although studies are concluding that may not be universal, they do allow farmers to grow more crops with higher nutritional yields on less land. 

9. But the FDA doesn't test GMOs
The FDA doesn't test genetically modified foods for safety, instead relying upon the industry itself to determine any ill effects. While that's been likened to how the pharmaceutical industry brings new medicines to market, you won't see Pfizer or Merck ignoring the agency's call for more data.

Because the GMO review system is voluntary, genetically engineered food makers can simply ignore requests for additional information. In fact, 50% of the time when the FDA asked for more data, the food developer didn't comply, and the FDA had to make a decision based on incomplete information.

10. Cross-pollination with conventional crops is a threat.
Genetically modified crops threaten traditional farming through cross-pollination. An Australian farmer lost his organic certification after his crops were contaminated, and there have been several instances this year where GMO wheat -- which isn't even grown in the U.S. -- was discovered growing in fields. Whether on the wind or through pollinators like bees, the potential for cross-contamination remains large.

Non Gmo Product Certified

Not even Non-GMO Project verified foods can be assured of being GMO-free since they use a threshold of 0.9% in alignment with European Union laws requiring any product over that amount be labeled.

11. USDA-certified organic crops may still contain GMOs.
The probability, and even the likelihood, of cross-contamination is acknowledged by the U.S. Agriculture Dept., which says that trace amounts of GMOs are permitted in crops even though they're labeled "organic." So long as the farmer didn't use genetically modified organisms in its processes, inadvertent detection of GMOs doesn't violate the standards. 

It's in the genes
The medical community has largely come out in favor of GMOs and says they're safe, posing no more harm to humans than conventionally grown foods. But that avoids the question of whether those who choose to not ingest genetically engineered foods have a right to know whether the products they're buying contain them.

The electoral battles recently fought are likely only just the latest skirmishes in a war that will grow in intensity as the awareness of GMOs expands, or until federal agencies adopt a single, coherent national policy.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool's board of directors. Follow Rich Duprey's coverage of all the most important news and developments in retail and consumer goods. He owns shares of Pfizer. The Motley Fool recommends Chipotle Mexican Grill and Whole Foods Market. The Motley Fool owns shares of Chipotle Mexican Grill and Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.