Horse DNA found in beef bolognese sauce has forced the British supermarket chain Asda to withdraw products from its shelves.

Apart from horse, pork DNA has also been discovered in one of its products, conceded the Wal-Mart Stores' British arm. The chain has more than 500 shops across the UK.

"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 As you'd expect, we have withdrawn this product from our shelves. 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," said the supermarket's spokesperson Jo Newbould.

Initial tests have proven the presence of horse DNA in the 500g beef bolognese sauce. Along with the product, Asda has withdrawn three other meat products - 600g beef broth soup, 500g meat feast pasta sauce, and 400g chilli con carne soup - as a precautionary measure. Asda said the products were made in Bristol at Greencore's plant.

Meanwhile, a French firm has been accused of labelling horsemeat products as beef prompting the French government to cancel its licence.

The food processing company, Spanghero, has been blamed for knowingly selling the products made of Romanian horses.

"The investigation shows that Spanghero knew that the meat labelled as beef could be horse. There was a strong suspicion," French Consumer Affairs Minister Benoit Hamon told a press conference.

"Did the meat arrive at Spanghero with the same label of 'Beef, origin EU' which is the label that it left with? No. It arrived with a label that said 'product of Romania, meat on the bone', but on the bill and the carrier information there was a customs code for horsemeat," he said.

Hamon added that Spanghero appears to be the "first agent in this chain" to dub the horsemeat products as beef. The French official noted that nearly 750 tonnes of horsemeat is involved in the scandal spanning at least 13 countries and 28 companies.

French officials said the firm has benefited by €500,000 (£430,000) by selling the cheap horsemeat as expensive beef products.

The French firm has denied the allegations saying: "Spanghero confirms having placed an order for beef, having been led to believe it received beef, and having sold back what it thought was beef, properly labelled as such, in line with European and French regulations."

The Hague-based European policing agency Europol is tasked with dealing with the spiralling scandal.