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

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

Chongqing Mayor Huang Qifan said the measures Wal-Mart took were rational and practical, adding that they show 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 the wake of the incident," said a Wal-Mart customer surnamed Chen.

The Chongqing Administration of Industry and Commerce conducted twice daily inspections of the stores during the closure period and gave administrative guidance for addressing management loopholes.

Earlier this month, Wal-Mart was ordered to close the stores and 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 sanctioned by the local government 21 times since 2006 for various violations, including false advertising and selling expired and substandard food.

The headquarters of Wal-Mart in China has sent a 60-member working team to Chongqing for the rectification work.

The Chongqing Wal-Mart stores confirmed they will improve the quality control system, strengthen the management of the pollution-free agricultural products, and set up a management monitoring mechanism for all goods for sale.

Pilot rapid food-testing rooms will also be set up in some Wal-Mart stores in Chongqing to facilitate the stores' food testing capabilities.

"All these measures are all taken to better protect customers' interests by facing the questions sincerely and striving to make improvements," said Del Sloneker, senior vice president of Wal-Mart stores in China.

The corrective actions of the Chongqing Wal-Mart stores will help us to provide better goods and services to customers. Every staff member will learn from that and deeply understand that integrity is at the core of the enterprise's values, and practice it, said Scott Price, president and CEO of Wal-Mart Asia.