Ms. Obama’s office said that Walmart “has been a strong partner” on the healthy-food front. “There’s still more to be done, but we look forward to continuing working with Walmart and others,” said Sam Kass, executive director of Let’s Move!, Ms. Obama’s anti-obesity program.

Yet growth has been slowing, analysts say.

“They’re still growing share and aisles at a tremendous rate, but not at the rate they were, in part because many of the established operators that are left today are pretty strong,” said Mark Hamstra, retail and finance editor of Supermarket News.

Walmart does well in dry goods, but fresh food requires more manpower to stock and rotate goods, involves more waste and is a higher-cost operation, he said.

According to the notes from the Walmart meeting last month in Orlando obtained by The New York Times, while Walmart has 20 percent of the market share in dry grocery, it has 15 percent in fresh (areas like produce, meat, deli and bakery).

Safeway customers are 71 percent confident in its fresh produce, the notes said, while Walmart customers are 48 percent confident in Walmart’s produce. In the interview, Mr. Sinclair of Walmart said he did not know where that data came from, but that “we believe that we can improve the perception of quality of produce for Walmart customers.”

The notes highlighted some stocking problems: “1 hour out of Refrigeration = 1 day less product life,” they read, adding that Walmart will change shift responsibilities so fresh food is not stocked overnight and goes out at 10 a.m., not 7 a.m. Also, Walmart will add secret shoppers to check on produce quality weekly, and add “would I buy it?” guides for employees, the notes said.

“What we’re trying to do this year is really accelerate the produce side of our business with better quality,” Mr. Sinclair said.