I did read the whole FDA online guidelines but can't recall where to find them, so I thought you'd all enjoy this small piece instead. For anyone interested though, just do some research for FDA related articles, guidelines and you may be able to find the complete foods listing etc.
This occurs in every country but the FDA related part was all I could locate online which is why it's USA related (don't anyone think for one minute that other countries go by a different standard); it's very clear that the UK uses feathers and hair in it's bread, pizzas, and doughs...Rich Tea biscuits don't, apparently, because I think they'd have to use that much that it's either illegal or too expensive.
What astounds me is the fact that cafes, restaurants and other places are checked for hygeine standards, isn't that a touch ironic, really? Anyway, enjoy a human hair with rat hair sandwich
I did some extensive research on the human hair aspect and it is used extensively in bread because it's cheaper than the synthetic version, only when the supply runs low (of human hair and duck feathers) do they resort to using the more expensive synthetic version in products and then only until such time as people go and get their hair trimmed again
Though it's dissolved in acid; in my mind both the acid and the hair are still both present...I'm no chemist but that hair is still there, it doesn't just vanish into thin air otherwise why bother with it in the first place...
...and next time you think it's cattarh, you may just surprise yourself when you hack up that furball
11 Disgusting Ingredients That Aren't Advertised In Food - Business Insider