Self-confessed Food Nerd

I am browsing through a book called Food in History by Reay Tannahill, hence the aforementioned "food nerd". And I couldn't believe this excerpt concerning food additives in the 1800s:

"China tea was green, and fake varieties were often produced from thorn leaves by drying them and then colouring them with verdigris, which was, of course, poisonous...The usual thing was for merchants simply to buy up used tea leaves from hotels, coffee houses and the servants of the rich, stiffen them with a gum solution and re-tint them with black lead. Even after treatment with verdigris or lead, however, tea was still a healthier drink than some of the 'gin' that had been sold a century earlier - compounded, according to one recipe, from ingredients that included sulphuric acid and oil of turpentine.
...crusted old port was new port crusted with supertartrate of potash; ...pickles owed their appetizing green colour to copper; ...many table wines gained their 'nutty' flavour from bitter almonds, which contain prussic acid; ...the rainbow hues of London's boiled sweets were produced by the highly poisonous salts of copper and lead; ...most commercial bread was loaded with alum; and ...the rich orange rind of Gloucester cheese came form ordinary red lead."