Is it safe to not wash mushrooms?
I have read a couple of experiments (in Dutch so I will not link them here) where people cooked the same dish from the same shrooms, with one batch brushed and the other washed.

The washed batch did need higher temparature to actually fry, instead of just boiling in their own moisture and the texture in the finished dish remained different. There does seem to to be some merit to the culinary traditions here.

As for the safety aspects, perhaps this will ease your mind somewhat:

Research minimizes effects of federal produce standards on mushroom industry:


  But a new study shows that heat generated during the traditional composting process -- originally developed to kill insect and fungal pests of mushrooms -- is adequate for eliminating human pathogens that might be present, according to researchers in Penn State's College of Agricultural Sciences.


If you got sick from eating a dish, the cause may not have been in the nutrition beds the shrooms were grown on.