If you know which are unsafe, you could have a threshold confidence, say the algorithm classifies one as shiitake with 90% probability but some unsafe mushroom

If you know which are unsafe, you could have a threshold confidence, say the algorithm classifies one as shiitake with 90% probability but some unsafe mushroom at >40% probability (or some percentage that makes sense), it could say, "looks like this is a shiitake, but careful it could be <unsafe mushroom>, here's some pictures and info about <unsafe mushroom>."