What are the facts and fiction about mushroom identification?

FACT: There are no non-scientific tests or rules that can accurately determine the safety or toxicity of a mushroom. Using the following "rules" could prove to be a deadly mistake.

FICTION: A mushroom is considered poisonous if:

• The mushroom stains when bruised
• The mushroom secretes a milky sap
• The mushroom turns garlic blue or black when cooked together
• The mushroom turns a silver coin black when rubbed against it
• The mushroom tarnishes a silver spoon when cooked with it
• The mushroom has scales, warts or other types of rough surfaces

FICTION: A mushroom is considered safe if:

• The mushroom grows on wood
• Slugs or other insects eat the mushroom
• Squirrels, rabbits, or other wildlife eat the mushroom
• The mushroom is dried, boiled, salted or pickled in vinegar
• The mushroom does not have a ring or skirt on the stalk
• The mushroom is pure white in color

FACTS:

• Some people can eat mushrooms with no problems, while other people eating the same mushroom will experience severe vomiting and diarrhea.
• Some people can have allergic reactions to eating "safe" mushrooms.
• Some mushrooms are only poisonous if eaten in large quantities.
• Some mushrooms are poisonous when raw but become harmless when parboiled and thoroughly cooked.
• Some mushrooms are poisonous regardless of how they are cooked or prepared.
• Some mushrooms are poisonous only if eaten with alcoholic beverages.
• Some mushrooms are classified as poisonous because they are hallucinogenic.

MORE FACTS:

• Some mushrooms that are edible when fresh and young become poisonous when they are old, hit by frost or if they decay.
• Some mushrooms, for unknown reasons, are poisonous in one part of the country and are not poisonous in another.
• Some mushrooms that are poisonous to animals do not cause major problems in humans.
• Most mushrooms are more dangerous to young children, the aged and the very ill.
• Ideally, people and animals should never eat mushrooms that have not been identified by an expert or bought at the store. Unfortunately, many mushrooms are difficult to identify even for a trained mycologist, a biologist trained in the study of mushrooms.

Poisonous Mushrooms

Mushroom poisoning, also known as mycetism, refers to deleterious effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells. Mushroom poisoning is usually the result of ingestion of wild mushrooms after misidentification of a toxic mushroom as an edible species. The most common reason for this misidentification is close resemblance in terms of colour and general morphology of the toxic mushrooms species with edible species. Even very experienced wild mushroom gatherers are sometimes poisoned by eating toxic species, despite being well aware of the risks.

To prevent mushroom poisoning, mushroom gatherers need to be very intimately familiar with the mushrooms they intend to collect, including knowledge of the toxic species that look similar to these edible species. Other considerations regard methods of preparation and toxicity of some fungal species that appears to vary with geographic location, raising the potential of mushroom poisoning due to local toxicity of a correctly identified species.

What symptoms do poisonous mushrooms cause?

There are a variety of mushrooms, divided into categories or groups. Each category causes different symptoms.

Group 1. CYCLOPEPTIDES: The first signs and symptoms may not develop for six to 24 hours, usually 10-14 hours after the ingestion. Symptoms begin with sharp abdominal pains, followed by violent vomiting and persistent diarrhea, often containing blood and mucous. In three to four days, the patient begins to worsen with symptoms of kidney and liver failure. Death is very possible.

Group 1A. ORELLANINE: Symptoms begin 36 hours to 11 days after ingestion. They include nausea, lack of appetite, headache and, most importantly, a severe burning thirst and kidney failure.

Group 2. IBOTENIC ACID-MUSCIMOL: A state resembling alcohol intoxication develops 30 to 60 minutes after ingestion. Confusion, muscle spasms, delirium and visual disturbances, which last for about four hours, develop following the intoxicated state. Vomiting usually does not occur. Drowsiness and sleep follow and recovery is usually rapid.

Group 3. MONOMETHYLHYDRAZINE: After six to eight hours, the patient experiences a feeling of fullness in the stomach followed by vomiting and watery diarrhea. Headache, fatigue, cramps and intense pain in the liver and stomach regions occur, followed by jaundice. Seizures occur in severe cases.

Group 4. MUSCARINE-HISTAMINE: Within 30 minutes to two hours after ingestion, symptoms include sweating, drooling, diarrhea, watery eyes, blurred vision, pinpoint pupils, decreased heart rate and blood pressure, and asthmatic breathing. (The sweating, drooling, diarrhea and watery eyes do NOT occur with other types of mushroom poisonings.)

Group 5. COPRINE: Symptoms will occur if this mushroom is eaten by a person who drinks alcohol within the next 5 days. Flushing of the face and neck, a metallic taste in the mouth, numbness of the hands and feet, palpitations, and an increased heart rate are the symptoms.

Group 6. PSILOCYBIN-PSILOCYN: These are the hallucinogenic mushrooms that alter consciousness. An intoxicated or hallucinogenic condition begins between 30 and 60 minutes after ingestion. The mood may be apprehensive (anxious) or pleasant. The person may experience compulsive movements and uncontrolled laughter. In children, a high temperature (102-106½ F) with seizures may develop.

Group 7. GASTROINTESTINAL: Within 30 to 90 minutes of ingestion, sudden severe vomiting and mild to severe diarrhea with abdominal cramps occurs. Symptoms generally last six hours. In children, this may lead to dehydration severe enough to require hospital treatment.

The growth cycle of mushroom

How do mushrooms grow?

Most mushrooms reproduce asexually by releasing thousands of spores through their gills into the open air for dispersion into the environment. Every spore is capable of germinating to create a new hypha. Hyphae are masses of intertwined filaments of cells which are the morphological unit of the fungus. When a thick mass of hyphae forms it is called mycelium or mycelia. Mushroom mycelium is usually white in color with a rough, cottony texture. Root like growth is called rhizomorphic.

When spores germinate they consume the water and nutrients from their environment and begin to reproduce. The medium that mushroom mycelium grows on is usually called substrate. Before the mushroom can start to form fruit bodies the mycelium colonizes the substrate fully and when the environmental conditions are right the mushroom emerges to produce more spores.

A mushroom cultivator can take advantage of the rapid growth mushroom mycelium exhibits by introducing it into new, sterile substrates. The mycelium is so tenacious that a 10 cc culture syringe can inoculate 10 quart jars of rye substrate, the preferred medium of most cultivators, and those in turn can be multiplied up to 10,000 times their weight. The true potential of mushrooms has yet to be taken advantage of.

mushroom varieties

WHITE BUTTON

White buttons or agaricus bisporus is the most popular mushroom, it represent about 90 percent of mushrooms consumed in the United States.

Taste. They have a fairly mild taste and blend well with almost anything. Their flavor intensifies when cooked.

Preparation. They can be sautéed or cooked any way or enjoyed raw in salads.

Uses. Try them sliced and sautéed on pizza, in pasta, quesadillas or cheeseburgers.

Nutrition. A serving of 4-5 white mushrooms provides 18 calories, 0 grams of fat and 3 grams of carbohydrates, yet is a good source of the antioxidant selenium; B vitamins riboflavin, niacin and pantothenic acid; and copper. And, mushrooms have close to 300 mg of potassium per serving, an imprtant nutrient that many Americans do not get enough of. White buttons also contain 2.8 mg of the antioxidant ergothioneine and 15 IU of vitamin D.

CRIMINI MUSHROOM

Crimini is also known as baby 'bellas or browns. The Crimini variety is similar in appearance to the white mushroom and belongs to the same species (Agaricus Bisporus). It has a light-tan to rich-brown hat and a firmer texture.The Crimini mushroom is the Portobello mushroom at the initial growth stage.

Flavor. Criminis have a deeper, earthier flavor than whites which makes Crimini mushroom an excellent option for many kinds of dishes.

Preparation. Sauté, broil, microwave or cook almost any way. The Crimini can substitute for or be combined with any recipe that calls for white mushrooms. Also it serves as a vegetarian entrée or as a side dish.

Uses. Their hearty, full-bodied taste makes them an excellent addition to beef, wild game and vegetable dishes.

Nutrition. A serving of 4-5 crimini mushrooms provides 23 calories, 0 grams of fat and 4 grams of carbohydrates, yet is an excellent source of the antioxidant selenium, the B vitamin riboflavin and copper; and a good source of potassium, phosphorus and B vitamins niacin and pantothenic acid. Criminis also contain 4.9 mg of the antioxidant ergothioneine.

PORTABELLA MUSHROOM

Portabella is a larger relative of criminis, Portabellas have tan or brown caps and measure up to 6 inches in diameter.

Flavor. They have a deep, meat-like texture and flavor.

Preparation. Portabellas can be grilled, broiled or roasted and served as appetizers, entrees or side dishes.

Uses. Their hearty taste and texture makes them a flavorful vegetarian alternative - grill and serve them as "burgers" on toasted buns.

Nutrition. One medium Portabella cap provides 22 calories, 0 grams of fat and 4 grams of carbohydrates, yet it is an excellent source of the B vitamin riboflavin; and a good source of the antioxidant selenium, potassium, phosphorus, the B vitamins niacin and pantothenic acid and copper. Portabellas also contain 4.3 mg of the antioxidant ergothioneine.

OYSTER MUSHROOM

The latin pleurotus refers to the sideways-growth of the stem with respect to the cap while the latin ostreatus (and the English common name, Oyster) refers to the shape of the cap which resembles the bi-valve of the same name. Many also believe that the name is fitting due to the flavor resemblance to oysters. The oyster is one of the more commonly sought wild mushrooms, though it can also be cultivated on straw and other media. Oysters can be gray, pale yellow or even blue, with a velvety texture.

Flavor. Oysters have a very delicate flavor.

Preparation. Sauté with butter and onions to bring out their flavor.Oyster mushrooms are best when cooked. Sauté or fry oyster mushrooms in butter or oil for up to 5 minutes, or cook them with a small amount of liquid in a covered pan for 10 to 15 minutes. After the mushrooms are cooked, add them to soups, sauces, or casseroles.

Uses. Try over linquine with sliced steak and red peppers, sprinkled with grated parmesan cheese.

Nutrition. Studies have shown that the mushroom could lower blood glucose and cholesterol in diabetes patients.

What is mushroom?

A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus, hence the word mushroom is most often applied to fungi (Basidiomycota, Agaricomycetes) that have a stem (stipe), a cap (pileus), and gills (lamellae, sing. lamella) on the underside of the cap just as do store-bought white mushrooms. However, "mushroom" can also refer to a wide variety of gilled fungi, with or without stems, and the term is used even more generally to describe both the fleshy fruiting bodies of some Ascomycota and the woody or leathery fruiting bodies of some Basidiomycota, depending upon the context of the word. Forms deviating from the standard form usually have more specific names, such as "puffball", "stinkhorn", and "morel", and gilled mushrooms themselves are often called "agarics" in reference to their similarity to Agaricus or their placement in the order Agaricales. By extension, "mushroom" can also designate the entire fungus when in culture or the thallus (called a mycelium) of species forming the fruiting bodies called mushrooms.