Not to single myself out as a total nerd here... But this idea is not far from fruition. Although I do not know of any phosphorescent (glow in the dark) pigments approved for food use, meaning you will not find any glow in the dark foods, nor do I know of any chemiluminescent or bioluminescent foods either, I do happen to know a certain fungi that fits the bill.
The Luminescent Panellus, which is perhaps the commonest of several different mushrooms that glow in the dark, can actually be seen glowing rather steadily as it ages. That being said it has a very peppery-hot to the tongue taste. It's considered inedible, but non-toxic. It isn't even known to cause gastrointestinal cramping like other non-toxic mushrooms can. Where am I going with this... right I remember now...
It likely could be ground down into a powder and achieve the same luminance, although flavor factor would be...well lets just say less than desirable...
