Even though you commonly find bell peppers on grocery store shelves, once you get them home - green peppers should always be refrigerated. They're best stored in your vegetable crisper in a resealable bag.   If you accidentally leave a sliced pepper out at room temp, the pepper's skin keeps it protected from drying out and rotting. Still, store sliced veggies properly in the fridge as soon as you can.   And since food poisoning is never fun - when in doubt, throw it out.