WASHINGTON — The only obstacle between kids and their french fries: Mom.

So here is Debra DeMuth, McDonald's global nutrition director, mounting a spirited defense of fries to five mothers of young children at a McDonald's in Baltimore.

"They are probably one of the most victimized foods," DeMuth says.

Plausible reason: A medium order at McDonald's, besides the delectable taste, includes 380 calories, 270 milligrams of sodium and a color preservative called sodium acid pyrophosphate. But DeMuth presses her case, pointing out that fries are rich in potassium, adding, "They are also a really good source of fiber."

One mom replies, "Once you throw them in grease, you kind of ruin it."

Another says, "Potassium is good in bananas."

This is the tricky dialogue that results when the world's largest fast-food chain extols the quality of its food to a group of people — busy moms — who often need food fast but don't necessarily trust fast food, especially with worries over obesity sweeping the nation.

But McDonald's thinks it has a positive case to make and has recruited mothers to go behind the scenes of the company's operations, meet senior executives and then communicate what they see via the Web, along with appearing in video of their travels.

The idea behind the company's Quality Correspondents program: If McDonald's can win over moms by showcasing food quality (the eggs in Egg McMuffins are real) and highlighting healthy options, the company can brighten its image at a crucial time in the arc of the fast-food industry.

Customers, bombarded with news about food recalls, are paying more attention to safety, quality and ingredients — despite still not wanting to wait very long for their lunch. The message takes on heightened importance now, as cash-strapped parents bargain in their heads over whether a McDonald's meal can take the place of higher-priced options.

"McDonald's has a problem," said New York University nutritionist Marion Nestle, author of "What to Eat." "They're big, so they are an easy target. They sell junk food and they market it to kids at a time when public obesity is a major public concern. So what are they going to do? Turn into a health-food company? I don't think they can do that. Somebody must have figured out that what they need is good PR on transparency. Those mothers are willing to be used for that purpose."

One of the moms, Veronica Gilmore, from Edinburg, Va., said no one tried to tell her what to say.

"We've been told to tell our perspective on things," she said. "That's all we can ask for."

McDonald's executives are betting that if they can shatter myths about the company's food — a chicken slaughterhouse visit shows the animals being handled humanely but also proves the Chicken McNuggets are real — and display an obsessiveness with food safety and quality to a select group of moms, the message will trickle through society.

Jerry Swerling, director of the University of Southern California's Strategic Public Relations Center, said McDonald's is attempting to capitalize on a significant shift in who consumers most trust for information.

"When people are asked to define who they trust and who they believe, the answer is people like themselves, not journalists and not academics," Swerling said.

A recent Edelman study showed most Americans think "a person like me" is the most credible source for company information.

"Word of mouth is not just a different kind of messenger," the study said. "It's a fundamental change in the traditional value system of information."

The Internet offers a fast word-of-mouth tool, and McDonald's is featuring the moms with diaries and video on its Web site.