Leaching of cadmium, lead and mercury from fresh and differently preserved edible mushroom, Xerocomus badius, during soaking and boiling

Many mushroom species are known as cadmium, lead or mercury accumulators. A possibility to decrease the metal levels was therefore investigated. Leaching of the metals from fresh, freeze-dried, air-dried and frozen slices of widely consumed Xerocomus badius was tested in three experiments. Common culinary treatments, soaking in 0.3% table salt solution at ambient temperature for 5, 10 or 15 min or repeatedly for 3×5 min and boiling in the same solution for 15, 30 or 60 min, were investigated. Short-time boiling was observed as a more efficient operation than soaking. The metals were leached to the greatest extent from the most destroyed tissues of frozen mushroom slices, but less so from fresh or freeze-dried tissues. The most extensive leaching was observed for cadmium and the lowest for mercury.