The contamination of meat products with horse DNA was most likely due to fraud and prosecutions should be pursued, according to a second British parliamentary report into the scandal.
"The evidence suggests a complex network of companies trading in and mislabelling beef or beef products which is fraudulent and illegal," said Anne McIntosh, a legislator who chairs the cross-party Environment, Food and Rural Affairs Committee, which published the report on Tuesday (16 July).
Europe's horsemeat scandal broke in January when traces of horse were found in frozen burgers sold in Irish and British supermarkets, including those run by market leader Tesco, raising questions about the safety of the European food supply chain.
"We are dismayed at the slow pace of investigations and seek assurances that prosecutions will be mounted where there is evidence of fraud or illegality," said McIntosh.
The report was critical of retailers, arguing they should have been more vigilant against the risks of adulteration, especially where meat products were traded many times.
It recommended retailers carry out regular DNA tests on meat and meat-based ingredients which form part of processed or frozen meat products, reporting results to the Food Standards Agency (FSA).
The additional cost of this testing should be borne by retailers and not passed on to consumers, it added.
"Consumers need to know that what they buy is what the label says it is," said McIntosh.
Britain's grocers have responded to the scandal by increasing testing, while Tesco, for example, has pledged to be more open about its supplier base.
The report did, however, conclude that the scandal, was not as extensive as originally feared. A study by the same parliamentary committee in February said the contamination discovered by that date was likely to be the "tip of the iceberg".
The new report said testing of processed and frozen beef products sold in Britain since January found horsemeat contamination was limited to a relatively small number of products with more than 99% of those tested found to be free of horse DNA.
It said tests across EU member states found 4.66% of products tested contained over 1% horse DNA.
However, in separate EU-mandated tests for the presence of veterinary drug phenylbutazone (bute) in horses slaughtered for human consumption, the UK had the largest number of positive results.