As Richard North has pointed out on EuReferendum, it seems likely that this is organised crime working on a continental scale and taking full advantage of the EU's fundamental free movement of goods principles. Containers of ciggies or cognac attract all sort of official attention, but no-one pays attention to twenty tonnes of frozen ground meat.
You may detect a certain lack of outrage here and this is because my beef consumption has been 95% prepared by me from fresh identifiable whole pieces of meat. And even though I've bought fresh supermarket mince to date, the purchase of a kitchen mincer (below) will allow me instead to process myself the cheap pieces of skirt or shin from the local butchers that I usually use for gulas.
And as for the FSA, their obsession with the minutae of health-fascist campaigning for 'healthy' food traffic-light labelling and the like has left the goal wide open for this greater adulteration. Perhaps a few sackings at the top are due.