A food safety watchdog has confirmed that one-fifth of meat samples tested in 2017 contained DNA from animals that weren’t listed on the label.
Among products testing positive for undeclared meat were dishes from three supermarkets and convenience stores, the Food Standards Agency (FSA) said.
A BBC Freedom of Information (FoI) request to the watchdog revealed that out of 665 results from England, Wales and Northern Ireland collected, 145 were partly or wholly made up of unspecified meat.
Results came from hundreds of businesses, including restaurants, convenience stores and supermarkets.
It showed that some samples contained DNA from as many as four different animals, while others contained no trace of the meat that appeared on the product's label.
Meat labelled as lamb was most likely to contain traces of other animals' DNA, followed by beef and goat.
Cow DNA was the most commonly-found contaminant, followed by pig, chicken, sheep and turkey.
An FSA spokesman told the BBC that it was up to the relevant local authorities to lead individual investigations and take "appropriate action" such as prosecutions.
