Most 1-pound meatloaf recipes require at least 40 minutes in a preheated 350 F to 400 F oven. Meatloaf and all other ground meats must be cooked to an internal temperature of 160 F or higher to destroy harmful bacteria.
To check the internal temperature, insert a meat thermometer in the center of the loaf. Never rely on the color of the meat to check doneness. Certain vegetables and herbs, such as bell peppers, onions and parsley, contain nitrates that may prevent meat from browning completely. In gas ovens, small amounts of carbon monoxide, which may be released from the heating element, can also alter the color of the cooked meatloaf.