China has ordered a crackdown on domestic ingredient makers after it was discovered one plant had been illegally producing a base for soy sauce made out of human hair.

A recent China Central Television report uncovered a factory in Hubei province that had been processing over ten tons of human hair daily into edible amino acids suitable for turning into soy sauce.

Rich in proteins and amino acids human hair was until recently widely used to make food ingredient L-cysteine worldwide. Such products pose no human health risks so it is unclear why China has banned their use in food.