CHONGQING - Thirteen Wal-Mart stores in southwest China reopened on Tuesday after being closed down by local authorities for 15 days for selling incorrectly labelled pork.

The company set up supervisory teams at stores in the city of Chongqing to improve management and overhaul product labeling during the temporary closure.

Chongqing Mayor Huang Qifan said the measures that Wal-Mart took are rational and practical, adding that they demonstrate the company's sincerity and willingness to assume responsibility.

"Although the stores were ordered to be closed after being accused of cheating customers, I hope they will correct their mistakes in wake of the incident," said a Wal-Mart customer surnamed Chen.

The Chongqing Administration of Industry and Commerce conducted inspections of the stores twice a day during the closure period and gave administrative guidance to address management loopholes.

Earlier this month, Wal-Mart was ordered to shut the stores down, as well as pay a fine of 2.69 million yuan ($423,000), after the stores were found to be selling ordinary pork labelled as more expensive organic meat.

The company has been disciplined by the local government 21 times since 2006 for a variety of violations, including false advertising and selling expired and substandard food.