A week after a New York City investigation found that Whole Foods Market Inc. stores were overcharging for prepackaged products, the company’s co-chief executives admitted pricing mistakes were made.

“Straight up, we made some mistakes,” co-chief Executive Walter Robb said in a video posted Wednesday.

Co-chief executive John Mackey said the “very, very small percentage” of “mis-weighing errors” occurred in fresh products like sandwiches, cut fruit and fresh squeezed juices.

“It’s understandable, sometimes, that mistakes are made,” Robb said. “They’re inadvertent.”

He said they knew the errors were “unintentional” because the mistakes were both “in the customer’s favor and not in the customer’s favor.”

Mackey said the company would increase training across the country and implement a third-party auditing system to check on progress. In 45 days, he said, the company will report back to customers.

In the meantime, Mackey said customers could double-check with cashiers if they think there is a pricing mistake. If they are being overcharged, they will get the product free.

The New York City Department of Consumer Affairs investigation tested the packages of 80 different kinds of prepackaged products and found that all of them showed mislabeled weights on their labels.

One example was a vegetable platter, which was priced at $20. The department inspected eight of these packages and found that customers were being overcharged, on average, by $2.50. One package was overpriced by $6.15.

Commissioner Julie Menin said inspectors told her it was the worst case of mislabeling they had seen in their careers.