Employees stand in front of the entrance to a Walmart Supercenter in this file photo taken in Chongqing, China on Oct. 24, 2011. Shi Tou/Reuters

Walmart Stores, the world's largest retailer, has recalled donkey meat sold at some outlets in China after tests showed the product contained the DNA of other animals, the U.S. company said.

Walmart will reimburse customers who bought the tainted "Five Spice" donkey meat and is helping local agencies in eastern Shandong province investigate its Chinese supplier, the company said late Wednesday in official posts on Weibo, China’s Twitter-like social networking site. The Shandong Food and Drug Administration earlier said the product contained fox meat.

The scandal could dent Walmart's reputation for quality in China's $1 trillion food and grocery market, where it plans to open 110 new stores in the next few years. China is the largest grocery market in the world and it is set to grow to $1.5 trillion by 2016, according to the Institute of Grocery Distribution.

"This is another hit on Walmart's brand, meaning wealthy shoppers will start to lose the trust they had before," said Shaun Rein, Shanghai-based managing director of China Market Research (CMR) Group. CMR estimates Walmart's market share fell to 5.2 percent from 7.5 percent over the last three years.

Donkey meat is a popular snack in some areas of China, although it only accounts for a tiny fraction of overall meat consumption. In 2011, China slaughtered 2.4 million donkeys, according to country's livestock industry yearbook.