The peanut shells are inexpensive and bulk up the cumin. So, in they go.
I personally doubt that any factory worker or any producer or owner thought they were putting anyone at risk.
And I also personally doubt that this was not a known additive, a known procedure in the industry. For years.
(As an aside-- walk down the spice aisle
in any supermarket and see the empty rows where cumin and paprika--and chili powder sometimes too. )
Fillers are used in every kind of food--I'm often amazed what foods include whey or other milk products, which ingredient I always thought was expensive.
But it's discouraging to feel that so many products can be contaminated at the source and that we'll never know.
I know you, like I, often cook from scratch since most packaged products contain something our kids can't eat. And that's the LISTED allergens.
This is a whole different ball game-- this is an unknown lurking danger. Or the possibility of danger-- and that's unnerving.
So the only option I feel I have is to make everything from scratch and to use salt, pepper and herbs...
Other spices-- I'd grind my own, but will
Probably forgo spices altogether.
Be well and we'll all have to make Italian food-- no need for cumin, paprika-- plus it's what I know best!