I just opened a pack of baby bella mushrooms that I bought yesterday. They were firm and in good condition, but the one on the bottom had wispy white threads growing out of the top. I thought it could be mold, but it also seems possible it was the mushroom's own mycelium growing out. None of the others had it. I threw it out along with the ones touching it, but I wonder, could anyone else more knowledgeable in mycology tell me if it was unsafe mold or not?