Checking out the Bible reference, the context there is that Jesus has just appeared to the disciples and they expressed some doubt, thinking that they were seeing a ghost. Jesus asks them if they have something to eat and, when they produce a piece of broiled fish, eats it, proving he is corporeal.

There was a play on this in the old comic strip Pogo when they think Howland Owl was a ghost. Someone suggests running a red hot poker through him. Owl notes that a ghost might scream as if in pain, just to fool them. He goes on to say that the only sure test is to feed him. If he holds the food he's not a ghost.

This, however, doesn't seem to match the context given by Ilango.