Fortunately Salzedo lets me know rather quickly. If he is going to eat, then it is a rapid feeding response, solid constriction, and quick swallow. If he is not interested, then he will sniff the offering, turn his head the other way, and act completely uninterested. After that there is nothing I can do to coax him into taking a bite, so I just accept his wishes and wait it out another few days.
IMO all BPs have their own little personalities, so consider my own experience with that in mind.
* I feed F/T or P/K