Horse burgers

Mary had a little lamb
And when she saw it sicken
She shipped it off to Packingtown
And now it's labelled chicken

           This was written in in 1906 when public outcry over dubious meat practices in American led to the passage of the Federal Meat Inspection Act of 1906
          In the UK in 1980 there was a 2 year investigation into the sale of horse, kangaroo, donkey, buffalo, knacker meat etc  and it was found to make up about 10-15% of meat used in products such a burgers and sausages.Legislation was introduced which was meant to prevent this happening again
          What has gone wrong.