This election season, California has become the frontline in the battle over genetically-modified foods, commonly called GMOs (the "O" is for organism). Soon, voters will decide whether nearly all foods with genetically-modified ingredients should be labeled. As is often the case with California, if it becomes law it's likely to become a national change -- putting GMO labels in grocery stores across the country.

The law wouldn’t take GMO foods off the shelves, it would just put a label on them. But opponents say it’s the same thing. GMO, they believe, has become a scarlet letter. If you put it on a label, no one will buy it.

But that wasn't always the case.  

In 1994, Belinda Martineau was a scientist at a California-based biotech company called Calgene, working on a new product she thought would change the world. It was the world's first genetically-modified whole food, the Flavr Savr tomato.

“We used to say, 'This is something we’re going to tell our grandchildren about,'” she says.  

The Flavr Savr was genetically engineered to solve a problem that had bedeviled farmers since the advent of the modern grocery store: How do you get a ripe tomato to the produce aisle without squishing it to pulp?

Usually, farmers solve this by picking their tomatoes early, while they’re green and hard enough to be transported in bulk by truck. The Flavr Savr was genetically engineered to stay firm even when ripe, "so you could pick it while it was ripening and still get it to market without turning into a pile of goo," Martineau says.

Martineau and others at Calgene knew some consumers might be scared of this new technology suddenly showing up in grocery stores. But they saw the Flavr Savr -- and the technology that created it -- as revolutionary., so they decided to market it that way.

"We thought if we were careful about it, and transparent," says Martineau, "we could convince the public that they should be as enthusiastic about it as we were."

No law required that the Flav Savr carry a GMO label, but Calgene decided to make technology a part of the advertising. Flavr Savrs were sold with tomato-shaped tags explaining genetic engineering technology and offering a 1-800 number, in case people wanted to learn more. 

It worked. In some markets, Flavr Savrs flew off the shelves. In Davis, where Martineau lives, the local supermarket had to set a limit: two Flavr Savrs per person, per day. "How they kept track of that, I don’t know," she says.

Now, Martineau says there’s a lesson here. If the public understands the science, most people, at least, will trust the science. Not labeling, she believes, makes it look like there's something to hide.

The current Calgenes of the world seem to see things very differently. Over the last few months, biotech companies like Monsanto, Dow and DuPont -- along with supermarket brands like Sara Lee, Ocean Spray, and Heinz -- have spent tens of millions of dollars lobbying against the very same labels that the Flavr Savr wore as a badge of pride.

A lot of scientists feel the same way. Take, for example, Kent Bradford, who directs the Seed Biotechnology Center at the University of California, Davis. He says GMO labels "absolutely play on [consumers'] fears."

When customers see those “Made with GMO" labels, Bradford believes he knows exactly what they’re going to think: "Why would they be putting this on the label if it weren’t something I should be concerned about?"

Bradford sounds pessimistic, but maybe he's just being a realist. If Californians approve the labeling law, we will soon find out.

So whatever happened to the Flavr Savr, that game-changing tomato genetically engineered to be both ripe and firm?

"It didn't actually work that way," says Martineau

In the end, public perception didn’t kill the Flavr Savr. The technology itself failed. The tomatoes didn’t stay firm, so they had to be handled like peaches.  "It cost $10 a pound to get them to market," says Martineau, "and they were selling for $1.99 a pound."

That was a problem no label in the world could solve.