I was visiting an organic garden a few years ago and was told that the white petals of these flowers are edible. Indeed they are, the petals are sweet and a little bit acid. We have this feijoa bush in our front garden and in 15 years it has never flowered quite as spectacularly as this.
Not quite sure about how to use these petals. Working on some ideas, perhaps a fruit salad or alongside some carpaccio of something.