Nutrition: Naturally low in calories and high in fiber, most mushrooms contain about 15 calories per 1 cup raw (sliced or pieces). Six medium-size white buttons have about 22 calories. Their micronutrients vary by species, but most edible mushrooms are considered a good source of vitamin D, thiamin, riboflavin, niacin, vitamin B-6, pantothenic acid, phosphorus, potassium, copper and selenium.
Selection: Look for mushrooms with firm stems and uniform color. They should feel light and dry, but not dried out or shriveled. Avoid any that appear bruised, feel slimy or have discolored stems that look like rotting wood (all signs of aging). Very fresh mushrooms may appear to have a papery layer of tissue on the cap (that’s good). The brown “dust” on cremini, button and portobello mushrooms is actually mushroom spores (they’re OK).
Storage: Moisture ruins mushrooms quickly. Store fresh unwashed mushrooms in a paper (not plastic) bag in the refrigerator for up to one week. Plastic traps moisture and encourages slimy mushrooms.
Preparation: Clean just before use. Brush or wipe off any dirt. It’s OK to wash mushrooms, but don’t let them sit in water. Instead, clean them gently under running water and immediately pat dry.
Dried alternative: Many gourmet mushrooms are available dried. Rehydrate them before use by soaking in hot water for 15 to 20 minutes.
Mushrooms vs. toadstools: While many mushrooms are safe to eat, poisonous varieties – often referred to as toadstools – contain toxic compounds but may closely resemble their tasty relatives. For example, poisonous amanita looks very similar to delicious cremini. When foraging, the wrong choice can be deadly. Proper identification is a must.