Maryann Ortiz was intrigued when she saw a television commercial that said Bakersfield and Fresno were the only places in the state where Taco Bell was selling its new Doritos Locos Taco, so she swung by the nearest one to check it out.

"I'm not a big Doritos person, normally," Ortiz said. "But I was curious."

She tried the new taco made from a Doritos shell more than a week ago, and has been coming back for another one almost daily ever since.

"It's really good," said Ortiz, an office manager for an air conditioning company, who was munching one on her lunch break Friday. "I think it'll go national."

It just might, if enough Central Valley residents are similarly enamored.

Irvine-based Taco Bell is the latest in a long line of companies that have run new products by the fine people of Bakersfield before nixing the offering or rolling it out nationally.

The company declined an interview request, saying it didn't want to skew the test results.

Oak Brook, Ill.-based McDonalds used Bakersfield to test the Angus burger in 2004, and later McCafe specialty coffees and fruit smoothies.

Blockbuster, headquartered in Dallas, tested a new price plan for movie rentals here in 2008 (it didn't stick); and Jack in the Box, of San Diego, chose the city to experiment with a Chipotle-like restaurant chain called JBX that fizzled in 2005.

Bakersfield often is used as a guinea pig for retailers and restaurants.

The city is attractive, companies say, because its small size and limited number of locations holds down costs.

"You can get your arms around 33 restaurants here versus more than 600 in a city like Los Angeles," said McDonalds spokesman Jim Darling. "If you think about spending $100,000 per restaurant on training, new equipment and marketing, if it flops in Los Angeles, that's a $3 million flop."

It also doesn't hurt that the region is a transportation hub, with its thriving rail network and the growing number of industrial distribution centers at Tejon Ranch.

If there's physical material to be shipped here, you can get it here fairly easily.

Bakersfield also has diverse racial and economic demographics, and the increasingly important Hispanic market is well represented here, said Marlene Heise, owner of local advertising agency Heise Media Group.

It doesn't cost as much to air television commercials here as in some larger markets, Heise said, so you can do very market-specific ad campaigns, such as the Taco Bell commercials airing now that mention Bakersfield by name.

In the ad, a pitchman says, "Bakersfield and Fresno, the 99, it's your time because you're getting Taco Bell's new Doritos Locos Taco, a new classic Taco Supreme with a shell made of real nacho cheese Doritos chips. San Francis-no, Sacrament-no, L.A. N.O. because the only places in California to get the Doritos Locos Tacos are Bakersfield and Fres-yes."

The tailor-made commercial probably is a smart move, Heise said.

Another reason Bakersfield is an attractive test market is the "psychographics" here -- that is, favorable buying habits, Heise added. For fast food outlets, in particular, this is a dream laboratory.

"Bakersfield is a big fast food market," Heise said.