I believe this was a subject discussed on television the other evening, either in a news report or mini documentary. There was also deep concerns about labelling, and how some people don't have a clue what's in the item they are actually purchasing.
The whole laws on marketing, labelling and additives want changing urgently in my opinion, and perhaps more so on how the label or packaging shows an item, like a chicken or any other similar food product, yet the actual content of that product can be very low (ie 5/12%) with the remainder being something entirely different.
A typical case is fish and chips, a stable British food diet. See a sign stating fish and chips, and the fish can be anything from the fish world. But it was only after Trading standards made sample purchases around the country that they find the widescale abuse of this practice. Vietnamese River Cobbler was being sold as cod or haddock, because the price for River Cobbler was far less. You wanted or expected cod or haddock, but you may have received something far less and didn't realise it?.
We had Doner Kebabs on Tuesday from our local Kebab/Pizza/Burger shop. Their boast is that they have been in business in the same shop for 25 years. They have a 'Safer Food' award and a Food Hygiene rating of 5, so I have no problem with buying from them. Their Motto is 'Quality is not a Chance, it is a Choice'. The shop is spotless and the preparation area at the back of the shop is open to view.
As do virtually all Kebab shops the large spit of meat for making Kebabs is bought in from an outside supplier, and these are the people who need to be investigated. The shop can only rely on what they are supplied with and can't be expected to know the composition of the product, but should expect to be supplied with the proper product.