The 44-year-old is leaving Del Taco on Nov. 17th and will serve as a consultant to the company.

In her new role, Lopez will work with Del Taco's senior management team on menu development and legislative issues, according to the company.

Lopez's full-time departure from Del Taco comes after a 30-year career at the restaurant chain.

She landed her first job at 14 wiping tables and mopping floors at Naugles, the Mexican fast-food chain that grew to 225 restaurants before it was sold to Collins Food International Inc. and took on the Del Taco name in 1988.

Lopez is leaving the company because she wants to focus on the next chapter of her life, she said.

"I am excited at the prospect of having the time to explore new interests and opportunities," Lopez said in a statement.

Nick Shepherd, chairman and chief executive of parent company Sagittarius Brands Inc. of Nashville, Tenn., will assume Lopez's duties with no immediate plans to fill the vacant role of president, according to the company.

"While I'm sad the business will no longer have the daily infusion of passion that Shirlene provides, I'm happy she is allowing herself the occasion to go and write the next chapter of her life," Shepherd said in a statement. "She is a constant promoter of the brand, and we'll all miss her."

Del Taco is the third-largest restaurant chain based in Orange County, according to the Business Journal's July list of restaurant chains.

The company has yearly sales of $550 million and counts 975 workers at 67 restaurants in the county.

Del Taco has carved a niche as a Mexican-flavored burger chain. Its menu has burritos and tacos to cheeseburgers and French fries.