Sandwiches sold in cafés, kebabs, stock cubes and other beef-based products will be checked as part of a wider investigation into the horsemeat scandal.
The Food Standards Agency (FSA) said 514 products would be sampled as part of an “expanded” survey.
The first two phases of sampling will be carried out by 28 local authorities and will include beef-based foods that are sold pre-packed or loose, such as café sandwiches.
An FSA spokesman said: “We have widened our testing to ensure that we get a more accurate and wider picture.
“The first reports of contamination were specific to certain products, such as beef burgers. But as intelligence about more beef products has been coming in we need to make sure our work reflects this.”
The third phase will see a further 150 samples taken and checked for horse DNA. Products such as gelatine, beef dripping, stock cubes, steak, stewing steak and ready meals that contain beef that is not minced will be included in the testing, which will begin next week.
The FSA said it would publish the results from the three phases of the study, including brand names.
“Initial findings will be available from the end of February and the FSA will disclose any formal action taken in April,” it added.
In the first set of industry tests, 29 samples out of 2,501 beef products tested in Britain were found to contain more than 1% horsemeat. The
FSA said the 29 samples, which related to seven products that had already been withdrawn, included Findus Beef Lasagne.
Mary Creagh, shadow DEFRA secretary, said the move to widen testing suggested that the problem of horsemeat adulteration was worse than first thought.
In other developments, Carmarthenshire food wholesaler Castell Howell Foods, which supplies 4,000 customers, said it had withdrawn cottage pies supplied by Oak Farm over possible horsemeat contamination.
Managing director Brian Jones said: “Supplier reports received to date have confirmed that ingredients are in accordance with declared product specifications, with the exception of the multi-portion cottage pie product supplied by Oak Farm, which has been recalled as a precaution due to the possibility of containing some horsemeat.”He added: “Customers affected have been contacted and sales of this product have been suspended pending further notification from the manufacturer. At this point in time, no other Oak Farm products are known to be affected.”
The House of Commons said four Brakes beef products, including pies, had been withdrawn from its restaurants as a “precautionary measure”.
And Nestlé – the world’s biggest food company – withdrew Buitoni beef pasta meals from supermarkets in Italy and Spain after traces of equine DNA were discovered in them.
Nestlé Europe said in a statement: “There is no food safety issue, but the mislabelling of products means they fail to meet the very high standards consumers expect from us.”