Mexico is one of the few places in the world—such as the Mediterranean, Mesopotamia and Southeast Asia—that was one of the first cradles of agriculture. The first plants to be domesticated were chili and corn. Archaeologists have found evidence of domesticated chili seeds in the valley of Tehuacan, Puebla, in Tamaulipas and Oaxaca that date back to between 7000 and 5000 B.C.
No other country is associated to such a degree with the consumption of corn and chili as is Mexico, where they are a key part of our identity.
The Olmec mother culture dates from about 20,000 BC, as do the crops that have been the mainstay of our diet for centuries: corn, beans, chilies and squash, grown on a milpa, a crop-growing system that combines these complementary crops. The technique known as nixtamalization—where the corn is soaked with lime, ash or pulverized shells—also dates from those times, as do kitchen utensils such as the molcajete, our mortar, to prepare sauces.
Source: GORTARI, Yuri.- La Cocina Mexicana, historia milenaria. Come and eat.