Horsemeat scandal: Full story will never be known, says FSA
15 February 2013 Last updated at 23:29 GMT
The chief executive of the Food Standards Agency has said it is unlikely that the number of people who have unwittingly eaten horsemeat will ever be known.
But Catherine Brown said she remained "confident" that the testing was the right way to address the issue.
The discovery of horsemeat in beef products has led to a range of processed foods being withdrawn from sale across Europe.
Retailers and suppliers have been conducting further tests to try to determine to what extent, if any, horsemeat is contained in their products labelled as beef.