Washing mushrooms or not washing mushrooms is an interesting thing. If someone washes mushrooms, it is most commonly because that’s what their parents or grandparents. And today, people are being much more cautious about any potential germs or bacteria that could be on their food.
Mushrooms tend to act like a sponge, where they will absorb any liquid that is put on them, including when you’re quickly washing them. Some people are still understandably squeamish when they see dirt on mushrooms, and want to wash them. However commercially grown mushrooms are raised in a sterile environment, so you don’t need to worry about any bacteria that could make you sick being on the dirt on the mushrooms you buy at a regular grocery store.
Because of mushrooms acting like a sponge, you definitely don’t want to wash them, but you can use a mushroom brush in order to easily brush the dirt off the mushrooms without damaging the mushroom. These are available at kitchen supply stores as well as places like Amazon. This is a nice solution for people who are still squeamish about seeing the dirt but I also don’t want to impact the recipe by having waterlogged mushrooms, creating a waterier dish.