Horsemeat scandal: three more British suppliers raided Proving that a criminal offence has been committed isn't always straightforward. Where we can take firm enforcement action we will. A total of 29 out of 1,929 samples of beef products contained at least 1 per cent horse meat, but the agency warned that more contaminated products may be found. Many retailers missed the Food Standards Agency's 12pm deadline for testing for horse meat. Tests on another 900 samples are still to come. The contaminated samples were found in seven products. Tesco's Everyday Value frozen burgers and Everyday Value spaghetti bolognese both contained horse meat, as did the Co-op's frozen beef quarter pounder burgers. Three lines of Findus beef lasagne tested positive, along with beefburgers for the catering industry supplied by Rangeland, an Irish company. Two Aldi products, Today's frozen beef lasagne and special frozen spaghetti bolognese, also were also contaminated. All the contaminated products have been withdrawn from sale. The Food Standards Agency said the retailers tested the highest risk products first, such as beef lasagne and beefburgers. The agency said it is also carrying out its own "rigorous sampling" because of concerns that "criminal elements" are involved. It has asked local authorities to carry out a further 224 tests on samples at a range of retailers. Retailers have reassured the Food Standards Agency that the worst contamination has already been identified. Miss Brown said: "It is there responsibility to deliver products which are what they say they are. We are also carrying out our own sample which is set up to work out exactly what we need to do. We chose the products, we get the results. It is right that industry do 100 per cent checks but it is also right that we do an independent check ourselves. Catherine Brown, the chief executive of the Food Standards Agency, said: "More arrests are possible. We still have active lines of inquiry. We did enter three premises in England with the assistance of local authorities. We are not disclosing any information, there are too many things going on and it's too complicated.