Phenylhydrazines in the Cultivated Mushroom (Agaricus bisporus)

In 1986, American investigators reported that feeding mice raw Cultivated Mushroom (Agaricus bisporus) three days a week for lifetime, induced tumours in several tissues. This finding stimulated the Nordic Working Group on Food Toxicology and Risk Evaluation (NNT) to review the data on phenylhydrazines occurring naturally in A. bisporus, and to summarize what is known about the toxicicy of these compounds and the mushroom per se. Based on the concern expressed in the early Nordic review, dated 1991, a Nordic project was initiated a few years later aiming to provide and collect additional data, useful for an assessment of whether the consumption of A. bisporus constitutes a human health risk or not. During their work, the project group in 1996 organised a Nordic Seminar: Phenylhydrazines in the Cultivated Mushroom (Agaricus bisporus). They also arranged agaritine to be synthesized. Agaritine is the most abundant phenylhydrazine in A. bisporus (approximately 200-500 mg/kg fresh weight). The project group used the synthesised material to develop a chemical analytical method for agaritine, and to study to what extent storage and processing influence the level of this compound in ready to consume mushrooms. Some of the agaritine was used for toxicological studies. The present report from the Nordic project group on risk assessment of natural toxicants brings together available scientific data on occurrence and biological properties of the phenylhydrazines and related compounds in A. bisporus, as well as data on the mushroom per se. Based on these data a risk assessment on human consumption of the Cultivated Mushroom (Agaricus bisporus) is presented and recommendations for future studies are given.