The mushroom Agaricus blazei Murill was discovered in Piedade, state of São Paulo, Brazil, and sent to Japan to be studied for its medicinal properties. Studies in guinea pigs revealed antitumor properties, triggering Japanese importation of Agaricus blazei Murill from Brazil. Because of its high price on the international market, many companies and rural growers produce Agaricus blazei Murill as alternative crop to increase income, but because interest in this mushroom occurred suddenly there has not been enough time for the scientific community to investigate it and, technology used for its cultivation is still based on empirical rules. There are also some contradicting data regarding the classification of this mushroom, and its antitumor properties still need to be confirmed in humans.
From the early days of civilization, man has used fungi for the production of fermented foods and beverages, or directly as food. In Ancient Egypt, fermentation was considered a gift from the god Osiris, while ancient Romans attributed the emergence of mushrooms and truffles to lightening bolts cast to the earth by Jupiter (Alexopoulos et al., 1996).
For centuries, Asians have attributed curative properties to some mushrooms. Reports from China since about 500 BC, on the medicinal properties of Ganoderma lucidum (known in China as reishi) extracts, especially its anti-cancer properties, have been passed on generation to generation (Mizuno et al., 1995a; 1995c), and since the Ming dynasty (1620 AD), there have been reports on the medicinal properties of Lentinula edodes (shiitake) mushrooms, considered an elixir of life and possessing the ability to enhance `vital energy’ and cure colds (Mizuno, 1995a).
In the late Twentieth Century, researchers in Japan demonstrated the antitumor effects of a Brazilian mushroom, identified as Agaricus blazei Murill, which became subject of studies by several research groups (Kawagishi et al., 1988; 1989; Osaki et al., 1