Is it OK to use expired cornmeal?

Degerminated cornmeal keeps quality for up to a year past its date if stored at room temperature, and a couple of years if frozen. Whole grain variety is best for only a couple of months past its date. You can store degerminated cornmeal in a cabinet in the kitchen or pantry at all times.

Can rancid corn meal make you sick?

Taste. If you still really aren't sure if the cornmeal has gone bad, take a small amount and taste it. It should taste clean and a little bit sweet. If there is a strong flavor that is unappealing, chances are the cornmeal has turned and could make you sick if eaten.