Cadmium Accumulation in Agaricus blazei Murrill

BACKGROUND: Agaricus blazei Murrill has become a popular food source of high nutritional and medicinal values in many Asian countries. However there are growing health concerns on cadmium (Cd) accumulation by A. blazei. Experiments were conducted to investigate Cd accumulation patterns in A. blazei and to determine the impact of fruit body yield, yield components and phosphorus (P) uptake on Cd accumulation. RESULTS: Results showed that Cd concentrations in the substrates and in the subsequent fruit-bodies declined rapidly after the 1st, 2nd and 3rd wave of harvests. A quick rinse of fruit bodies in water can reduce Cd concentration by 27-54% depending on the strains. The Cd concentration in fruit bodies decreased as the fruit-body yield m-2 or fruit-body numbers m-2 increased, while it increased as an increase in the substrate Cd content or in the fruit-body size. Cd accumulation was positively associated with P uptake. CONCLUSION: These results suggest that Cd and P concentrations in the substrates and the casing soil should be reduced in order to effectively minimize Cd accumulation in the fruit bodies. It is also necessary to improve fruit body yield through increasing the numbers of medium-sized fruit bodies. The over-growth of individual fruit bodies stimulates Cd accumulation in A. blazei.