Whitbread revealed its meat lasagnes and beefburgers had been affected as it was confirmed for the first time that schools and hospitals had been supplied with food containing horsemeat.
Cottage pie testing positive for horse DNA was sent to 47 Lancashire schools while contaminated produce from Rangeland Foods in the Irish Republic was sent to hospitals north of the border.
The Local Authority Caterers Association insisted the Lancashire case was an “isolated situation”.
Shadow Environment Secretary Mary Creagh, the MP for Wakefield, said: “David Cameron has got to stop hiding behind the retailers and food industry and take decisive action to get a grip on this scandal now.
“He should order the FSA to speed up its testing so that we have a full picture of just how far this has spread in our communities.
“People will be shocked and dismayed that horsemeat has now been found in schools and hospitals.”
The Food Standards Agency yesterday said 2,501 tests had been carried out on beef products, with 29 results positive for undeclared horse meat at or above one per cent.
All the positive test results were connected to products already reported and withdrawn from sale – Aldi’s special frozen beef lasagne and special frozen spaghetti bolognese, the Co-op’s frozen quarter pounder burgers, Findus beef lasagne, Rangeland’s catering burger products, and Tesco value frozen burgers and value spaghetti bolognese.
Environment Secretary Owen Paterson said it was “wholly unacceptable” if products marked beef turned out to be horsemeat, which was why it was so important to undertake intensive testing activity to get the full picture.
He said: “My concern is for consumers. The news for them today is that the vast majority of products tested are completely clear of horse DNA.
“Food businesses now have a lot of work to do. They need to move quickly to complete these tests and they need to show their customers they’ve taken the right steps to make sure this doesn’t happen again.”
Downing Street tried to shift attention away from the Government, criticising retailers for remaining “silent”. But in a letter issued by 11 major retailers, caterers and other food companies including Tesco, Asda and Sainsbury’s, they said they understood and shared their customers’ “anger and outrage”.
“The food industry is determined to restore consumer confidence in the food we sell as quickly as possible.
“We can’t accept a situation where the trust customers place in us is being compromised by fraudulent activity or even, as alleged, an international criminal conspiracy.
“That is why we are acting together with the Government and the Food Standards Agency, not only to get to the bottom of how this has happened but to take whatever steps are necessary to reassure customers that they can trust the food they buy.”
The results published by the FSA did not include the tests for Whitbread which had sent 30 products for investigation.
A Whitbread spokesman apologised to customers for any “concerns or inconvenience” and said the company was “shocked and disappointed at this failure of the processed meat supply chain”.
Huddersfield University revealed it had started testing food products from local stores for both horsemeat and the painkiller drug phenylbutazone – known as ‘bute’ – which is given to horses.
The European Union unveiled more details of a new testing regime agreed earlier in the week which will see between 10 and 150 random DNA checks per EU country next month. The control system is almost certain to be repeated in April and May, according to officials in Brussels, depending on the initial findings.