One of the food companies at the centre of the horse meat scandal said it is considering taking legal action against its suppliers, as the Environment Secretary warned that there may be more cases of contaminated meat to come.
Owen Paterson said that results from tests on all retailers' and manufacturers' processed beef products could see further traces of horse meat being found.
He expressed concern that an international criminal conspiracy was taking place and made it clear the Government will work with authorities anywhere to ensure appropriate measures are taken.
Frozen foods firm Findus, which has taken its beef lasagnes off shelves after some were found to have up to 100% horse meat in them, said it was looking into legal action as an internal investigation "strongly suggests" that the contamination "was not accidental".
The company said in a statement: "Findus is taking legal advice about the grounds for pursuing a case against its suppliers, regarding what they believe is their suppliers' failure to meet contractual obligations about product integrity."
Mr Paterson spoke after attending an emergency meeting with bosses from leading supermarkets, trade bodies and the Food Standards Agency (FSA) to discuss the scandal which has seen chains including Tesco, Lidl, Aldi and Iceland withdraw some of its products.
The FSA have now asked retailers and processors to test all their processed beef products to make sure they are what they say they are.
"There may well be more bad results coming through, that's the point of doing this random analysis," Mr Paterson said.
He said retailers hold the "ultimate responsibility" for making sure that horse meat is not in their products and that the supermarkets and trade bodies at today's talks had agreed to look into how they can improve their existing regimes and have already begun plans to carry out more testing and report their results on a quarterly basis.
Prime Minister David Cameron has said the matter is "shocking" and "completely unacceptable". Labour leader Ed Miliband said: "I think people in the country will be quite shocked that horse meat has been in the food that they have been innocently buying. The Government has got to get a grip on this situation."