Plausible reason: A medium order at McDonald’s includes 380 calories, 270 milligrams of sodium and a color preservative called sodium acid pyrophosphate. DeMuth further points out that fries are rich in potassium, adding, “They are also a really good source of fibre.” 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 ensues 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. 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 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 and highlighting healthy options, it can brighten its image. McDonald’s executives are betting that if they can shatter myths about the company’s food 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 capitalise on a significant shift in who consumers most trust for information.