Flour and cornmeal are fine. Cornmeal is used to fatten fishing worms. Cardboard and kitchen scraps work too.

Finished compost can go into (or be sprinkled over) garden soil without a tea stage - there's an advantage to that because it will release nutrients gradually.

Cornmeal and flour should be used in small amounts. The can heat up and/or get very moldy. Mold is more of an aesthetic problem than anything else. Once the mold has done its thing, it will die, and leave behind a vermi delicacy. But you have to put up with the mold first.

Sprinkle very lightly and heat buildup will be minimal. But be minimal in all additions, until you figure out how they do in your bin. Locations change everything, so you have to find out what works in your home or garden space.

I would not purchase food for a worm bin, but if you have some outdated stuff go a head. Maybe use a parmesean cheese container to sprinkle a bit on each week so as to not have it heat up or cause issues.

It should be fine if you do not sprinkle a solid layer over your bin. I have read somewhere that when moist, it will built a film over it and be sort of a barrier for airflow. This is when problems start. Remember how people starched clothes in olden days?

otis11, no! I don't remember how people starched clothes in olden days. Will you tell me?