Absence of agaritine in Pleurotus species and in other cultivated and wild-growing mushrooms not belonging to the genus Agaricus

Agaritine, a naturally occurring phenylhydrazine derivative in the cultivated white mushroom Agaricus bisporus is considered a potential health risk. Consequently, consumers should have the choice of other edible mushroom species that are exempt of this compound. Present legislation lists 26 species of cultivated mushrooms - not belonging to the genus Agaricus - which were screened for agaritine with negative results (limit of determination: 0.03 % on dry matter). The popular Oyster mushroom, Pleurotus ostreatus, which has recently been reported to contain as much agaritine as A. bisporus, also tested consistently negative. Critical examination suggests that this report is based on poor methodology yielding false positive results. A study of the distribution of agaritine within the genus Agaricus (covering 32 spp.) revealed that the compound is often accompanied by the formylphenylhydrazine analogue agaritinal, which until now had only been isolated from the Meadow Mushroom A. campester. Members of the related genera Lepiota and Coprinus, as well as the hallucinogenic mushrooms that are increasingly recreationally used in Europe, were also found to be devoid of agaritine. The occurrence of this potential toxicant is truly limited to the genus Agaricus.