Although sources vary about the exact year bioengineered foods became a part of the American diet, by the time the California Right to Know Genetically Engineered Food Act received enough signatures to become a ballot initiative in the 2012 election, people all over the country had been dining on genetically modified crops and by-products for almost two decades already. Yet today, if you ask most folks if they know about this, you’ll probably be met with an incredulous stare.

The biotechnology industry has a long history in the United States. In the 1980s, scientists discovered that “specific pieces of DNA could be transferred from one organism to another.” This basic principle of modifying genes resulted in genetically engineered tobacco, cotton and soybeans that were resistant to either destructive antibiotics or herbicidal agents and pests. By 2000, scientists discovered that genetic modification could also enrich foods with nutrients and vitamins.

In 2011, when Pamm Larry decided to protest the widespread presence of genetically modified organisms (GMOs) in groceries, the raven-haired grandmother, a midwife and former farmer from Chico, California, launched a website and Facebook page that clearly stated her mission: “Label GMOs.” Then she connected with local activists against genetically engineered foods. That’s when she started to believe she could gather the required 504,760 signatures to get an initiative on the 2012 California state ballot demanding a law that would mandate the labeling of foods containing genetically modified ingredients.

With the help of volunteers, she secured almost 1 million signatures, which helped land the initiative on the ballot as Proposition 37. This pitted her against the massive biotechnology corporations that eventually killed the measure in California.

The corporations that kicked in the largest contributions to fight Prop 37 included agricultural research giants Monsanto and Dupont. Together, the two companies funded the “Vote No on 37” advertising war chest, with donations totaling more than $13 million. Other biotech businesses, such as Dow Agrisciences, Bayer Cropscience, BASF Plant Science and Syngenta Corporation, followed close behind with smaller individual company contributions of about $2 million.

Surprisingly, however, prominently represented on the list were also well-known organic and natural food brands. Brands such as Naked, Back to Nature, Kashi, Horizon Organic, Cascadian Farm Organic and Muir Glen, among others, opposed Prop 37 for a number of different reasons.

Some companies felt that labeling GMO foods might create misperceptions and cause confusion among consumers. Others argued that there’s no scientific evidence to support the belief that genetically modified foods are harmful.

The consolidation of the North American organic-food-processing sector started in 2002 when the government implemented a federal organic standard that replaced state and regional standards. Philip H. Howard, an assistant professor in the department of community, agriculture, recreation and resource studies at Michigan University, explored the increasing involvement of corporations in the organic food sector. “Some of these changes are well-hidden, as few companies that have acquired organic brands make these ownership ties apparent on product labels,” Howard wrote in a paper on organic industry structure published in the Journal of the New Media Caucus. “At least sixteen major organic brands have resisted enormous buyout offers and remained independent. The overall trend, however, is increasing industry domination by large, transnational corporations.”

Howard created a series of infographic charts to illustrate what he calls the “industrialization of organics” trend. In an animated version of the charts, shifting graphics show how transnational corporations restructured the industry with their acquisition of organic brands (a strategy called horizontal integration) and the introduction of their own organic products (a process termed concentric diversification).

Interestingly, many of the major organic brands that remained independent are reflected in one of Howard’s charts. All the ones listed there supported Prop 37, while those acquired by transnational corporations did not.

This changing landscape has became part of the backdrop against which a still nebulous “food movement” has struggled to solidify politically for almost 40 years, according to Michael Pollan, who discusses the issue in his article “The Food Movement Rising,” published in The New York Review of Books. Prop 37 came the closest to doing just that, not only in California but also on a national level.

Although Prop 37 was defeated, the debate thrust the labeling of GMO foods into the public health forum. “The whole country is waking up,” Larry told a meeting of grassroots advocates shortly after she learned the proposal was dead.

For those who’ve followed this fledgling movement, Prop 37’s demise probably seemed like déjà vu. Ten years ago, in Oregon, a coalition opposed to the labeling of genetically engineered foods received funding from biotech, grocery and agricultural industries. That money was used to bankroll a $4.5 million advertising campaign against Oregon’s pro-labeling initiative, Measure 27.

As in California, a majority of Oregon voters initially supported the proposition, according to at least one pre-voting poll. But three weeks later, once the coalition had launched its advertising attack, another poll showed that more than two thirds of voters would not support the measure, which later failed. The defeat in Oregon foreshadowed what happened in California. But the movement for mandatory labeling of genetically engineered foods continues unabated. Many states continue to clamor for the right to let people know what they’re eating.

Today, the movement to slap labels on products that contain genetically modified ingredients is still active. According to the Center for Food Safety, a national non-profit public interest and environmental advocacy organization, currently, more than 30 states have introduced at least 70 bills to require the labeling of these foods. Two states, Connecticut and Maine, passed laws requiring these labels if bordering states adopted similar regulations. Another state, Vermont, passed a bill supporting the labeling of GMO foods that’s set to become mandatory this July if it withstands legal challenges from the food industry.

Just Label It, a consumer advocacy organization that supports GMO labeling, notes,

“The issue’s not going to go away. These [campaigns] are going to just keep coming.”

Larry, whose Facebook page became a website (LabelGMOs.org) dedicated to requiring GMO foods be labeled, says that despite the difficulties advocates face in this fight, she remains optimistic.

“I believe in the power of the grassroots,” she says. “I believe that at the end of the day, it doesn’t matter what the huge corporations do. We’re on the side of truth and ethics and we will win.”