User blog comment:Plainblack/Blackbeard, the Enigma/@comment-6920514-20130904150642/@comment-6920514-20130904195046

Gotta disagree with you, PB. When Kaku and Kalifa were eating their DFs Lucci told them they had to eat the whole fruit. Also, as far as spitting it out Shanks tried to get Luffy to spit out his so I'd say it's possible to start but not finish a DF or spit out a DF and be fine.