I suspect the adulteration is mainly in prepacked items such as sausage, lasagne, curries and bolognese. At the end of the day it is all protein. How many slugs get tastefully presented in prepacked salads?
I caught the tail end of a TV program yesterday where a family were fast food addicts. If I heard correctly the analysis of their food intake over a period of time came up with 400 chemicals that I presume were additives of one sort or another. Even Mcdonalds has 78 additives on the menu.
The odd bit of dog or horse in a burger is merely the result of someone's money making scam. Perhaps long term the additives present a far greater danger to health. The goalposts are constantly changing. Many colourants were banned in Europe not so very long ago but I believe some are still allowed in the US.
It is a minefield.