If roaches devour flour, will it butcher them?
Answers: No, but they'll appreciate the meal.
Cream of wheat, grits and other rumors are matching. You'll just nurture them - they won't pop and it won't gum-up their mouth or butt.
If roaches were that straightforward to get rid of, why would anyone own them in their house? You have need of to buy some roach motels. They work because the roach is attracted to the scent and gets poison on it, later brings it back to the off the record roach nest and poisons all the tot roaches before it dies.