Cooked corn on the cob typically lasts in the refrigerator for five to seven days. Corn that has been removed from the cob and cooked stays fresh in the refrigerator for the same amount of time.
If corn begins to spoil, the tip of the corn becomes darkened and moist. Mold may also begin to form at the tip of the corn. Fresh corn that has been cut from the cob leaks a milky substance that can help indicate if the corn is still safe to consume. Corn should be thrown out if the liquid around the kernels changes in smell or color.