The corn tortilla. It's a symbol of Mexico that's been a mainstay of the national diet for some twelve thousand years.

Fifty-nine different types of corn are native to Mexico, yet food activists cite government studies showing consumption of the national staple has dropped by forty percent over the past three decades.

It's a trend that Rafael Mier, the founder of the 'Rescue Tortilla Consumption in Mexico' movement, blames on a number of factors.

"There are many reasons that Mexicans are eating fewer tortillas," Mier explained. "There are many more foods available in the market, foreign eating habits are being adopted, and the continuous migration from the countryside as people abandon their farms have all contributed to this loss of traditional culture."

As the tradition of making tortillas by hand is being lost, mass-production has grown, and quality is being compromised.

Hector Cruz owns a tortilla shop, and says there are practical considerations beyond just the taste. "A tortilla made with natural flour will be fresh for one to two hours, while a machine tortilla will remain fresh for up to fifteen days if refrigerated. The flour we use here has a preservative which stops the product from going to waste," Cruz said.

Cruz's clients know the difference too. One of them, Jose Manuel Garcia, said that, "In truth, I would prefer to eat hand-made tortillas, but it's easier to buy them from a dedicated shop close-by, so we come here."

Patricia Gonzalez is a nutritionist, and says the gradual loss of the hand-made tortilla from the Mexican diet is already having an effect.

"The way we prepare corn is called Nixtamalization," she explained, "before we make the dough for the tortillas, and in that process the corn gains more minerals. And we are able to prevent a lot of diet problems that we were having, especially with kids, by enriching the dough of the tortilla."

"Now we have other foods that are competing against it, and they are similar in price, but nutritionally they are not as rich, so that's where the problem lies."

Now, the government is warning of price hikes of as much as 25 percent for tortillas this year - fueling concerns consumption will be pushed lower still.

As the traditional handmade tortilla continues to lose ground to its mass-produced counterpart, health experts and food activists alike are decrying its disappearance. And while the corn tortilla is likely to remain a symbol of Mexican cuisine, its future appearance could become unrecognizable.