Question on dog food

I have heard it is bad to feed dog food to your rodents because of some dye that is in it that is bad for the snakes. is this true?

& 2nd if its a higher quality food that doesn't have the dye in the ingredients would you consider it fine to feed? ( I am merely talking supplementing them occasionally. I have my rodents on the mazuri pellet food)

Red dye #40 is supposedly bad.

As long as the dye isn't listed in the ingredients I think dog food is fine as a supplement to blocks.