Tests for horsemeat in processed meat products are being expanded, the Food Standards Agency (FSA) has said.
The survey has been widened to ensure that a wider range of products are sampled and will now include beef-based foods that are sold pre-packed or loose, such as cafe sandwiches.
A total of 514 products will now be tested for traces of horsemeat, the FSA said.
A further phase of testing is to follow the current two, which are continuing.
The third phase will see a further 150 samples taken and checked for horse DNA.
These include products marketed or labelled as containing beef as a major ingredient. Products such as gelatine, beef dripping, stock cubes, steak, stewing steak and ready meals which contain beef that is not minced, are included. Testing is due to begin next week.
The first phase saw 224 samples of minced beef products including burgers, minced beef, beef sausage or meat balls checked for horse and pork DNA, while the second, which started last Thursday involves 140 samples of beef-based ready meals including frozen, chilled or canned lasagne, chilli con carne, cottage pie, ravioli, cannelloni and spaghetti bolognese being checked for horse and pork DNA.
The sampling for the first two phases is being carried out by 28 local authorities while sampling for the third phase will be allocated to other local authorities across the UK.
The FSA will publish the results from all three phases of the study, including brand names with initial findings available from the end of the month.
The agency will disclose any formal action taken in April.