It used to be that if there was a hair in your food, you'd send it back. Not at a fast food joint -- where an amino acid called l-cysteine is used to condition bread dough to make it more pliable. L-cysteine, by the way, is made from duck feathers and human hair, and in fact, a few years back CNN reported that women in China were selling their hair to chemical processing plants making l-cysteine for the North American Market.