Is it Safe to Stuff a Turkey?
Why is it Not Safe to Stuff a Turkey?
Cooked stuffing needs to reach 165° F.
This is the same temperature that a turkey (located closer to heat sources than the stuffing) must reach to be considered safe to eat. This is a safety precaution because the stuffing comes into contact with the raw turkey meat when stuffed inside the bird, yet it cooks slower than the meat because of the positioning. The truth is that bacteria can survive in stuffing that has NOT reached 165°F, possibly resulting in foodborne illness. Last year, there were at least 107 hospitalizations due to salmonella in raw turkey  (and that number was prior to Thanksgiving!).
This is a warning from the USDA:
“Even if the turkey itself has reached the safe minimum internal temperature of 165° F as measured in the innermost part of the thigh, the wing and the thickest part of the breast, the stuffing may not have reached a temperature high enough to destroy bacteria that may be present.”
A thermometer cannot reach into the center stuffing to properly measure temperature.
It is recommended to cook turkey to an internal temperature of 165° F, as measured from the innermost thigh. Stuffing inside the cavity of a turkey is further inside than the innermost thigh. Therefore, stuffing may not reach a safe temperature to kill any bacteria that the turkey may have contained if a turkey is cooked to the proper temperature. If the turkey is cooked long enough to ensure that the innermost stuffing has also reached the 165° F temperature, then the turkey meat will most likely be dry.
Why is stuffing cooked inside a turkey potentially unsafe to eat?
Because meat juices came into contact with the stuffing as it was being stuffed and have been dripping into the stuffing as it heats slowly inside the turkey. There is plenty of opportunity for any bacteria that may have been present in the raw turkey to become harbored inside the stuffing. Since the stuffing is surrounded by bones in the central cavity, it will be the last part to reach proper temperature (and nearly impossible to reach with a thermometer).
So, why not wait until the stuffing reaches the proper internal temperature?
If you wait and take the turkey out once the stuffing has been properly cooked, then the turkey meat will most likely be overdone and therefore dry. Plus, it is difficult to find a thermometer long enough to reach the very center of the turkey.
But, don’t skip the stuffing!
The best advice is to cook a casserole of stuffing separate from the bird.
In summary, cooking a stuffed turkey is not the safest option. Given what can happen from eating undercooked poultry, it makes sense to cook stuffing outside of the turkey and not take any chances of getting a food borne illness or giving one to your guests. Besides, turkey and dressing are usually put into separate serving platters anyways, even when a stuffed turkey is prepared.