I knew I was going to get this reaction! I follow the bleach soak with an equally long clean water bath, followed by another water bath. I'm going for a sterilizing of any bacteria that can cause illness. When serving for a crowd, I try to keep cold foods below 40F and hot foods above 140F using chafing dishes (ice + water for the former, chafing fuels for the latter), but I can't guarantee that those temps will hold, thus the need to get rid of as many baddies like ecoli/salmonella/clostridium/etc before they can grow in the danger zone.You're adding bleach to your diet and you're worried about problems with mushroom powder?
I have seen sources using baking soda or vinegar and I'm tempted to give those a try. Though if bleach is good enough for Alton, it's good enough for me: