How the Taco Gained in Translation

SAN BERNARDINO, Calif.

ADMIT it, tortilla-chip fans: you are curious about Taco Bell Doritos Locos tacos, introduced in March. These salt bombs take the usual fast-food taco filling and stuff them inside a giant orange-dusted nacho-cheese chip. They have been so successful that the company has just introduced a Cool Ranch flavor.

But to truly grasp the significance of these creations, the taco must be eaten in the company of Gustavo Arellano, a journalist and Orange County, Calif., native who is perhaps the greatest (and only) living scholar of Mexican-American fast food. And preferably, you will eat it here, in the birthplace of American fast food, while he explains to you precisely how the Frito, America’s first corn chip, was copied from the Mexican tostado, then evolved into the Dorito and eventually the Tostito.

He has just published “Taco USA,” an absorbing account of how a few foods (salsa, tacos, chili, tequila) from the complicated and enormous cuisine of Mexico managed to slip into the mainstream of American taste.

“It’s not exactly a feel-good story, except maybe for the shareholders of Frito-Lay,” he said, gesturing out to the empty storefronts and cash-only gas stations that line the streets.

San Bernardino, an hour east of Los Angeles, is the fertile crescent for American fast food, but its west side has clearly seen better days. In 1940, the first McDonald’s drive-up hamburger stand opened a few blocks from this Taco Bell; throughout the ’40s and ’50s, entrepreneurs came through town to check out the McDonald brothers’ revolutionary technology hacks — like single-serving ketchup dispensers, burger-size spatulas and disposable milkshake cups. (In 1954, Ray Kroc, a salesman of milkshake mixing machines, came through town and was so impressed that he bought in, started his own franchise, and later bought the brothers out.)

The evolution of Mexican food in the United States is the current obsession of Mr. Arellano, the editor of The OC Weekly, a lively journal where he has also been the food critic for the last 10 years. He has spent much of that time exploring precisely how Mexican food became so popular and profitable in this country — where, until very recently, most things Mexican were generally both unpopular and unprofitable.