Horse meat could have been in beef burgers for years but remained undetected because of insufficient food regulation, it has been claimed.
The UK's food watchdog, the Food Standards Agency (FSA), is considering taking legal action against companies at the centre of the scandal.
The FSA said it would consult relevant local authorities and the Food Safety Authority of Ireland (FSAI) over whether to take action against any organisations embroiled in the controversy.
But the organisation was criticised for not carrying out tests in the past because horse meat posed no threat to public health, the Daily Telegraph said.
Tim Lang, a professor of food policy at City University in London, told the newspaper: "It could have been going on for years but we wouldn't know about it because we have never conducted tests. For too long we have had light-touch regulation. The Food Standards Agency has to be institutionalised into taking a more critical approach. They have to work on the assumption that things could go wrong."
After a meeting with food industry representatives, the FSA said it would continue its review of the traceability of the food products identified in an FSAI survey, which uncovered the scandal. It also said it would try to further understand how the lower levels of horse and pig meat contamination took place and help to carry out a UK-wide study of food authenticity in meat products.
Meanwhile, the food company at the centre of the scandal vowed to adopt strict DNA testing of its products to prevent a repeat. The ABP Food Group, one of Europe's biggest suppliers and processors, is being investigated by health and agriculture authorities in the UK and Ireland over the controversy.
Two of its subsidiaries, Silvercrest Foods in Ireland and Dalepak Hambleton in Yorkshire, supplied beef burgers with traces of equine DNA to supermarkets, including one product classed as 29% horse.
An ABP spokesman said: "It is vital that the integrity of the supply chain is assured and we are committed to restoring consumer confidence."
A third company, Liffey meats, based in Co Cavan, Ireland, was also found to be supplying products to supermarkets with traces of horse DNA.