Holy cow is there strong opinion on this question. Here’s what my research turned up:

The folks at the FDA were adamant: “Scrub them gently under cool running water, then dry them off—as thoroughly as possible—with a paper towel or clean cloth after washing.”

Researchers for the organization, STOP FOOD-BORNE ILLNESS added: “They should be washed. And remember to keep unwashed mushrooms from contacting surfaces with ready-to-eat items like lettuce, cucumbers, or any other produce that will not be cooked.”

From experts at the American Mushroom Institute, who didn’t say “YES, absolutely!” or “NO, it’s not necessary.” Instead, they just explained how to clean them: “To clean mushrooms, brush off any debris with fingers or a damp paper towel, or rinse briefly and pat dry with a paper towel.” To me, “rinse briefly” isn’t the same as full-on washing.

All advice from the PRO-WASHING people was prefaced with this note: “Do not wash them until you are actually ready to use them, to prevent them becoming soggy or moldy.”

As I dug deeper, though, I found that professional chefs don’t agree with the agencies or organizations mentioned above. Those I studied were united in believing that the question should be aimed more at uncultivated mushrooms grown in the wild. Cultivated mushrooms are grown in sterile environments in sterile peat moss, not dirt. Here’s just one example of the prevalent philosophy from the pros:

Chefs from the 26-yr-old cooking school, Chicago’s Chopping Block, said “Cultivated mushrooms which are grown in sterile environments are the bulk of the mushrooms that you will encounter. As a rule, cultivated mushrooms do not need to be washed due to the sterile environment and medium in which they’re grown. All you need to do is brush them off with a dry towel or mushroom brush.

“And there is a subtle difference between the idea that you don’t need to wash cultivated mushrooms and the statement, ‘You should never wash mushrooms.’ It’s a serious overstatement to say it’s a big no-no to wash mushrooms. Actually, most of the time you shouldn’t full-on wash a mushroom; but there are times it is essential to wash a mushroom (such as those found in the wild, growing in dirt.)”

So why do chefs, the folks who deal in preparing excellent foods on a daily basis, have such a strong reaction to washing mushrooms? Because it can ruin them. No matter how well you pat them dry, they’ll retain water and can quickly go soggy and moldy (as mentioned above).

My take on the question is this: Federal agencies always lean to the extreme; they have to cover their derrieres. So, I take what they say with a discerning eye. The folks who are in the food trenches day after day seem to be grounded in more common sense and actual experience. Thus, I’m prone to follow their counsel, which is: cultivated mushrooms should be wiped with a paper towel or gently brushed with a mushroom brush. But if you can’t live without washing them, then do it only before you’re going to use them.

Lastly, here’s maybe the best advice of all: The two most important issues with protecting your mushrooms from early deterioration are temperature and ventilation. Temperature-wise, keep them in the refrigerator. And ventilation-wise, take them out of the plastic containers and store them in a brown paper lunch sack. This will allow air to flow and will keep them fresher longer.

What’s YOUR take on this subject? Do you wash your mushrooms or dry brush them? And finally, was any of this helpful? We’d love to know your take on this question, so reply if you have a minute? Meanwhile, here’s a wonderful mushroom recipe to whip up while you’re thinking about this question.