Does corn casserole spoil if left out overnight?

Yes, corn casserole spoils if left out overnight. Corn casserole is a perishable food that contains meat, dairy, and vegetables, all of which can spoil quickly at room temperature. The USDA recommends that perishable food be refrigerated within 2 hours of cooking and that it be consumed within 3-4 days. Leaving corn casserole out overnight significantly increases the risk of foodborne illness.