Horse meat has been found in UK firm Findus' beef lasagnas. This happened just weeks after horse and pig DNA was found in its burgers.

CNN reported that 60 percent and 100 percent horse meat was found in Findus lasagna according to food inspectors.

"Findus said it had withdrawn its lasagna -- labeled with the British spelling, "lasagne" -- from stores Monday as a precaution after its French supplier, Comigel, raised concerns about the type of meat used. All other Findus products are unaffected, it said," reported CNN.

This discovery comes after the Food Safety Authority of Ireland found 10 out of 27 hamburger products it analyzed contained horse DNA while 23 had pig DNA in it.

At the time Prime Minister David Cameron said according to Reuters, "People in our country will have been very concerned to read this morning that when they thought they were buying beef burgers they were buying something that had horse meat in it. This is a completely unacceptable state of affairs."

Simon Coneney who is Ireland's Agriculture Minister said that a meat processor in County Monaghan which is on the border with Northern Ireland was to blame, the AP reported. He said to broadcaster RTE that an additive in the burger had horse meat in it.

In nine out of ten burgers horse DNA was found at low levels but in Tesco's burger's, a popular British retailer, horse meat was accounted for 29 percent of the burger.

Now, the chief executive of the Food Standards Agency, Catherine Brown, said that UK firms must test all their beef products by next Friday.

"The FSA is now requiring a more robust response from the food industry in order to demonstrate that the food it sells and serves is what it says it is on the label," she said to CNN. "We are demanding that food businesses conduct authenticity tests on all beef products, such as beef burgers, meatballs and lasagne, and provide the results to the FSA. The tests will be for the presence of significant levels of horse meat."

There have been raised concerns that the meat could contain a veterinary drug phenylbutazone which is commonly used to treat horses and could pose a human health risk.

Findus has been ordered to test the lasagna meat from the shelves to make sure there is no phenylbutazone in it.

"We understand this it is a very sensitive subject for consumers and we would like to reassure you we have reacted immediately. We do not believe this to be a food safety issue," Findus said in a statement.