6. Slime mold occurs with mushroom packs that have been harvested from many times and placed at the bottom of barns shelving or hanging arrangements. Yellow fibers are clearly visible on the side and around the opening of the packs. This usually occurs with Wood Ear Mushrooms whose packs were cut on the side and watered for too long, so that the packs got soaked. It also occurs when using mushroom packs that haven’t been relocated during cleaning of the mushroom barn.