Wal-Mart Stores Inc's British supermarket arm, Asda, said on Thursday it had discovered horse DNA in its beef bolognese sauce and was withdrawing that product and three others from its stores.
"We have a preliminary test result that suggests the presence of horse DNA in our 500g Beef Bolognese sauce. As you'd expect, we have withdrawn this product from our shelves," Asda spokeswoman Jo Newbould said. Asda has about 550 shops across the UK.
(Read More: UK Lawmakers Say Horsemeat Discoveries 'Tip of the Iceberg')
"We are taking a belt-and-braces approach so in addition, as a precaution, we're also withdrawing three other beef-based products produced by the same supplier," she said.
The three other products are beef broth soup, meat feast pasta sauce and chilli con carne soup. Asda said it does not have positive test results for horse DNA in those products. It said the products were made at the Irish food group Greencore's plant in Bristol.
Last month, Asda withdrew four burger products after they were found to contain trace levels of horse DNA. The burgers were supplied by Silvercrest, which had also sold Tesco and other grocers beef burgers containing horse meat.
Separately on Thursday, Irish supplier Rangeland Foods said it was withdrawing its frozen burger products after discovering that some contained 5 percent to 30 percent horse meat. Rangeland supplies frozen burgers to restaurants, pubs, caterers and fast food chain Supermac's.
The discovery of horsemeat in products supposed to contain beef has rocked the food industry in Europe and Britain and triggered investigations into Irish and Romanian suppliers that sell products to major supermarkets.
Britain's Food Standards Agency (FSA) said on Thursday that six horses slaughtered in the UK that tested positive for the drug phenylbutazone were exported to France and may have entered the human food chain.
The drug known as bute is a common anti-inflammatory painkiller for sporting horses, but it is banned for animals intended for eventual human consumption because of concerns that it poses a health risk to humans.