Well, assuming you're not eating alive targets, you may be able to use http://geck.gamesas.com/index.php/KillActor, as it's dead already you can just use the Dismember limb integer. Not sure if this will work on already dead targets though.
That would work for Actors irrespective of their GetDead state, yeah.
That is, KillActor, when paired with the appropriate parameter, will dismember limbs. Remember to check Body Part Data numbers to know which limb you want to dismember. Since it sounds like you just want it to work on humanoids then this part will be easy - otherwise, you'd have to run checks for any possible actor-type whose Body Part Data differs from the standard before specifying the limb to dismember.
The function call would look like this:
DudeToBeEatenREF.KillActor DudeThatEatsREF 1;
In humanoids, the above call would dismember the head.
O.