A meat thermometer should be used to verify that turkey meat has reached the proper doneness. An ovenproof thermometer can be placed into a whole turkey and remain there throughout the roasting process. An instant read thermometer can be used to check the temperature of the internal temperature of turkey breast, but it cannot be left in the bird during cooking because it is not heatproof. Some whole turkeys are sold with pop-up timers that indicate when the turkey is fully cooked, but a meat thermometer is still the most reliable tool for determining the proper doneness. Shown below are a dial face ovenproof thermometer and an instant read digital meat thermometer that can be used to check the internal temperature of turkey to ensure internal temperature of turkey breast doneness.