This is going to sound wierd, but when my usual staph flares up it's somewhat sweet. When I had MAC and it was flared up my sputum tasted different - more of an orange flavor than the usual Kool Aid kind of flavor. When my lung bugs are held at bay there's not much of a discernable flavor. Also the color of the sputum changes, or actually the tint of it changes, from a yellow cast to a greenish and even a brownish tint. ~Juliet