Shiitake

Distribution and habitat

Shiitake grow in groups on the decaying wood of deciduous trees, particularly shii and other chinquapins, chestnut, oak, maple, beech, sweetgum, poplar, hornbeam, ironwood, and mulberry. Its natural distribution includes warm and moist climates in Southeast Asia.

Cultivation

The earliest written record of shiitake cultivation is seen in the Records of Longquan County (龍泉縣志) compiled by He Zhan (何澹) in 1209 during the Song dynasty in China. The 185-word description of shiitake cultivation from that literature was later cross-referenced many times and eventually adapted in a book by a Japanese horticulturist Satō Chūryō (佐藤中陵) in 1796, the first book on shiitake cultivation in Japan. The Japanese cultivated the mushroom by cutting shii trees with axes and placing the logs by trees that were already growing shiitake or contained shiitake spores. Before 1982, the Japan Islands' variety of these mushrooms could only be grown in traditional locations using ancient methods. A 1982 report on the budding and growth of the Japanese variety revealed opportunities for commercial cultivation in the United States.

Shiitake are widely cultivated worldwide, contributing about 25% of the total yearly production of mushrooms. Commercially, shiitake mushrooms are typically grown in conditions similar to their natural environment on either artificial substrate or hardwood logs, such as oak.

Toxicity

Rarely, consumption of raw or slightly cooked shiitake mushrooms may cause an allergic reaction called "shiitake dermatitis", including an erythematous, micro-papular, streaky pruriginous rash that occurs all over the body including face and scalp, appearing about 24 hours after consumption, possibly worsening by sun exposure and disappearing after 3 to 21 days. This effect – presumably caused by lentinan, a polysaccharide – is more common in East Asia, but may be growing in occurrence in Europe as shiitake consumption increases. Thorough cooking may eliminate the allergenicity.

Uses

Fresh and dried shiitake have many uses in East and Southeast Asia. In Chinese cuisine, they are used in many dishes, including soups, braises, and stir-fried vegetable dishes such as Buddha's delight. In Japan, they are served in miso soup, used as the basis for a kind of vegetarian dashi, and as an ingredient in many steamed and simmered dishes.

Two prized varieties are produced in cooler temperatures. One high-grade variety is called dōnggū (冬菇) (literally "winter mushroom") in Chinese, or donko (冬子) in Japanese. The most highly prized variety is called huāgū (花菇) (literally "flower mushroom") in Chinese, due to the flower-like pattern of cracks in the cap.

Nutrition

Raw shiitake mushrooms are 90% water, 7% carbohydrates, 2% protein, and contain less than 1% fat (table). In a reference amount of 100 grams (3.5 oz), raw shiitake mushrooms provide 34 calories of food energy, and are a source of several B vitamins and some dietary minerals (table).

Like all mushrooms, shiitakes produce vitamin D₂ upon exposure of their internal ergosterol to ultraviolet B (UVB) rays from sunlight or broadband UVB fluorescent tubes.