LOL, I think 95% of snakes in captivity today are proof that you are worried about nothing.
Why do I say this? It is easy. The hog feed I am using has Copper 16 - 19 ppm.
Mazuri 6F, what the great majority of Rodent breeders feed has Copper 22 ppm. https://www.mazuri.com/PDF/5M30.pdf
So yeah, if your worries are true, you better switch to the hog feed right away!