Lancashire County Council has suspended the supply of all frozen processed beef products to schools after tests found further traces of horse DNA.
The county council is one of the few councils in the country able to conduct its own laboratory tests on the DNA composition of meat products.
Council chiefs say they chose to test for traces of horsemeat in all the frozen processed beef products supplied to its schools.
It says the majority of affected products on school menus have tested negative for horse DNA, but two have tested positive.
The first was a pre-prepared cottage pie, which was revealed earlier this month and affected 47 schools.
Now more traces have been found in a second product – a Halal beefburger, which had been available at four schools in the county.
All affected schools have been contacted and informed.
County Coun Geoff Driver, leader of Lancashire County Council, said: “I hope that parents and children can be reassured by the advice that this isn’t a food safety issue, however it is frankly appalling that we have found horsemeat in two products which were supposedly 100 per cent beef.
“These products came from manufacturers who not only carry all the correct certification but who also recently provided us with written assurances their products did not contain horse meat.
“Few if any local councils across the country have been as proactive as we have in testing their school meals and unfortunately the results show we were right to act on the concerns raised by what has become an international scandal.
“Under the circumstances, with children returning from their half term break today, we feel we have no choice but to withdraw all frozen processed beef products as a precaution until the food industry and regulators do something to restore confidence in what people are being fed.”
Changes to the county council’s school meals menu will take place with immediate effect.