Odonna Mathews, the public face of Giant Food who dispensed cooking tips and nutritional advice with a comforting next-door-neighbor charm, is retiring after 28 years as the chain's consumer adviser, the company said yesterday.

During a tenure that spanned five chief executives and a series of tumultuous changes at the company, Mathews served as a powerful link to Giant's local heritage. Even after the chain was sold to a foreign company and merged with a supermarket chain in New England, Mathews remained, offering suggestions on how to cook 30-minute meals with five ingredients.

Giant executives said the chain's 40-person consumer advocacy department will remain intact and local, but Mathews's replacement will work out of Massachusetts rather than Maryland, the first such arrangement since the position was created in 1970.

In her role as consumer adviser, a position she took over in 1977 at age 27, Mathews was Giant's designated internal critic, charged with informing top executives of what shoppers loved and what they hated.

Over time, she took the region's biggest supermarket chain and humanized it, appearing in simple, unglamorous radio and television advertisements and dutifully responding to thousands of phone calls and letters from grumbling Giant shoppers.

"She was our secret weapon," said Dave Herriman, Giant's chief merchandising officer until 2000. "She gave us an edge our competitors didn't have. Other chains had consumer advisers, but you don't remember any of their names."

Mathews, who is 55, said she will step down at the end of the month to spend time with her two school-age children. She will be replaced by Andrea Astrachan, 36, a Washington native who now lives in Rhode Island.

Astrachan will work out of Quincy, Mass., home of Stop & Shop, which merged with Giant in 2004. Both chains are owned by Royal Ahold NV, a Dutch company. Mathews is consumer adviser for Giant's 200 stores and Stop & Shop's 360 outlets.

"It was the right time" to leave, Mathews said. "It was my personal decision."

Mathews's career encompassed Giant's period of explosive growth in 1980s, the death of its charismatic leader, Israel Cohen in 1995, and its sale to an out-of-town company in 1998.

That sale and merger proved rocky for employees and customers, weakening the chain's grip on the local grocery market. Ahold said yesterday that sales at Giant stores open for at least a year fell 4.7 percent in the second quarter of this year compared with 2004's second quarter.

Giant hired Mathews as an intern fresh out of a management program at the University of Maryland, where she had studied the work of the chain's previous consumer adviser, Esther Peterson.

Peterson became a legend in the grocery business, having pushed hard for truth-in-advertising laws that were eventually adopted by Congress. When Mathews was tapped for her job five years later, she was so nervous she "couldn't sit in her desk the very first day," Mathews said.

But Mathews quickly grew into her role as advocate in chief. She championed a wide range of health care and nutritional programs that advised consumers on how to avoid heart disease and illness from raw meat.

Mathews continually met with and interviewed Giant customers -- spontaneously in stores and in organized panels held at hotels -- and then lobbied for their suggestions with company executives.

Pete Manos, a former Giant chief executive, remembers opposing one of those proposals, to create a checkout lane free of candy. Parents had told Mathews they were tired of fighting their children over a Snickers bar every time they shopped. "Odonna was insistent on this," Manos said.

The chief executive made his position known, but the consumer adviser prevailed. "She wasn't afraid to tell me I was wrong," Manos said.

When Mathews wasn't fielding complaints from elderly men about the ripeness of the melon in the produce department, or calming mothers who had seen one too many scantily clad model on the magazine shelf, or assuring a seafood lover that the live lobsters in the seafood tank felt no pain, she recorded advertisements for radio and TV.

Hundreds of them. So many, in fact, over so many years, that she has burned through several company slogans. "Giant, the quality food people" gave way to "That's my Giant," and now "You've got a Giant on your side."

Newspaper archives are filled with her face and helpful advice. Her photo sits on the bottom right-hand corner of a full-page advertisement from a 1987 copy of The Washington Post. "Be a safe food handler," says the ad, which explains how to properly prepare meat, poultry and seafood. Mathews, smiling widely, encourages readers to "clip and save these tips for handy reference."

Tim Hammonds, chief executive of the Washington-based Food Marketing Institute, said Mathews and her predecessor invented the consumer adviser job for the supermarket industry. "They brought the voice of the consumer right into the boardroom, where decisions are made," he said.

Giant Food's Odonna Mathews is featured on the cover of a health-advice brochure. She has served as the chain's consumer adviser since 1977.

Andrea Astrachan is Giant Food's new consumer adviser.