Overview
Liu and colleagues characterized total cadmium content, chemical speciation (residual vs. acid-soluble forms), and in vitro bioaccessibility via simulated gastrointestinal digestion in six edible mushroom species purchased from commercial sources in China. Agaricus blazei contained the highest total cadmium (3.84 mg/kg). However, in vitro bioaccessibility of cadmium in A. blazei was low (approximately 6%), while no cadmium was detected in the bioaccessible fraction of the other five species. This suggests that cadmium primarily exists in insoluble residual fractions (cell walls) in most mushrooms, reducing actual dietary exposure relative to total content. The release of polysaccharides during digestion in A. blazei was proposed to partly govern cadmium bioaccessibility through adsorption and complexation mechanisms.
Key numbers
Total cadmium content (mg/kg fresh weight):
- Agaricus blazei: 3.84 mg/kg (highest; note this exceeds Chinese ML of 2 mg/kg fresh weight for mushrooms cited in the text; the Chinese national standard GB 2762-2022 sets the ML at 0.2 mg/kg fresh weight for mushrooms generally, while the study cites 2 mg/kg as a contaminant limit for some context).
- Lentinus edodes, Morchella esculenta, Cordyceps militaris, Lyophyllum decastes, Stropharia rugosoannulata: total cadmium values below the 2 mg/kg level cited in the study (specific values not fully extracted from pages reviewed).
Cadmium bioaccessibility (in vitro digestion model):
- Agaricus blazei: approximately 6% bioaccessible fraction (low).
- Other five species: cadmium not detected in bioaccessible fraction.
Cadmium speciation: primarily in residual (insoluble) state in Lentinus edodes, Morchella esculenta, Cordyceps militaris, Lyophyllum decastes, and Stropharia rugosoannulata. A. blazei contained detectable acid-soluble (exchangeable) cadmium alongside the residual fraction.
Chinese ML reference: GB 2762-2022 sets cadmium maximum at 0.2 mg/kg fresh weight for mushrooms (the study also cites a 2 mg/kg limit in some contexts; this page does not resolve that discrepancy and reports both values as stated in the source).
Methods (brief)
Sequential extraction with dilute acid and GFAAS for cadmium speciation. In vitro digestion model mimicking gastric and intestinal phases; bioaccessible fraction measured in digestate supernatant by ICP-MS. Shanghai Academy of Agricultural Sciences, National Engineering Research Center of Edible Fungi.
Evidence fitness
Mechanistic speciation and bioaccessibility study on commercially purchased Chinese mushrooms; important for understanding that total cadmium content overestimates true dietary exposure in most mushroom species. Limitation: purchased commercial samples with no reported growing conditions or provenance tracing; Agaricus blazei total cadmium (3.84 mg/kg fresh weight) substantially exceeds the Chinese ML, raising questions about source quality control. Bioaccessibility data use a single in vitro model; in vivo confirmation not available.
Related evidence
- Wild Mushrooms
- Mushrooms
- Wild Mushrooms
- Mushrooms — cultivated (button, cremini, portobello, oyster)
- Cadmium
Update history
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