Panorama journalists bought 17 boxes of frozen chicken fillets from various sources around the country.

Most of these chicken fillets had been imported from Holland, and were sent off to a Public Analyst Laboratory and the specialist company Indentigen to test them for their meat content and for traces of beef or pork DNA.

The results are featured below along with a link to the companies' responses:

CHICKEN
Manufacturer/brand	Meat content (declared)	Meat content (actual)	Cow DNA?	Pic DNA?
T Lelie	70% min	73%	Yes	No
T Lelie	N/A	N/A	Yes	No
den Hertog	80% min	76.6%	N/A	N/A
De Kippenhof	70% min	62.7%	N/A	N/A
De Kippenhof	65%	60.1%	No	No
Capri Chicken	80% min	76.6%	N/A	N/A
Slegtenhorst (MR Brand)	70%	64.7%	No	No
Slegtenhorst (MR Brand)	80%	71%	No	No
Lamex Sun Brand *	68%	72.5%	Yes	No
Lamex Sun Brand *	68%	66.7%	Yes	No
Jozef Hassan	N/A	53.5%	Trace	Trace
Seamark "Nice"	70%	66.2%	No	No
Seamark "Nice"	70%	68.5%	No	No
Vriesekoop "Duke"	80%	80.6%	Yes	No
Vriesekoop "Duke"	80%	60.4%	No	No
Vriesekoop "Theco"	N/A	N/A	No	No
Slegtenhorst chicken supplied by Brakes: product 3017	70%	51%	Yes	No

Source: BBC Panorama tests

* Product contains casein, a milk protein