Burger King has reintroduced some of the food colours associated with possible hyperactivity in children in a small number of restaurants, the Food Standards Agency (FSA) said.
The fast-food chain, which has 14 restaurants in Northern Ireland, is using the colours as a result of trialling the Coca-Cola Freestyle drinks dispensing system for six months until December.
The FSA said it had removed Burger King from its list of caterers and restaurants whose food and other products were free of the colours.
The vending machine allows customers to choose from a variety of flavours, but Coca-Cola was unable to remove all the colours associated with possible hyperactivity from the system before the trial, the FSA said.
It added that Coca-Cola had “reaffirmed its commitment” to remove the colours.
An FSA-funded study identified six food colours associated with possible childhood hyperactivity: E110, E104, E122, E129, E102 and E124.