[mulmen]

Do you have a source for this? What kind of material do they add?

[aaron695]

Sounds illegal - https://www.gipsa.usda.gov/fgis/grainhandling.aspx

Except -

"Recombine or add broken corn and broken kernels to whole grain of the same kind, provided, that no dockage or foreign material, including dust, has been added to the broken corn or broken kernels;"