What it is
Ground magnesium-silicate mineral — the talcum-powder material — used to keep powders free-flowing and polish candy and rice.
Why your biology objects
The mineral itself is inert, but it forms in the same geology as asbestos and can carry asbestiform fibres, which IARC classes as a Group 1 carcinogen. A cosmetic anti-caking job that brings a contamination question food never needed to raise.