A discussion about the source of Nicotine (NIC) in boletus (Boletus edulis) was started in the EU in 2009. No clear conclusion about the nicotine source in wild dried mushrooms was reached [1,2]. In 2010 the specific MRL of 2.3 mg/kg for dried wild mushrooms was established.
There was one single case of high nicotine content in cultivated mushrooms due to a nicotine-containing substrate of chicken feathers which had been deloused with nicotine. Various theses have been developed and disproved. As ever, the highest nicotine levels can still be detected in Chinese mushrooms, especially from the province Yunnan. Parallel to our study of nicotine findings in Indian tea, we postulated the ambient agro-climatic situation in China and more precisely in Yunnan could be the cause.
Besides being the most common location for the picking of boletus, Yunnan is the province in China, famous for its tobacco growing and production. NIC is highly volatile. It can be transported per air and condensed on the earth.
Altogether we measured more than 20 different dried mushrooms incl. for nicotine and for the main nicotine metabolite, cotinine. We also differentiated between the stump and the hut of the mushrooms and also analyzed sponge (boletus) as well as lamella (champignon) mushrooms. The NIC findings were higher in the huts of sponge mushrooms, followed by their stumps in Chinese products. We didn’t see any differences between NIC findings in different tissues of the lamella mushrooms, but we could identify the two following trends:
- Where the Cotinine/NIC proportion was 1-5 % we would ascribe the contamination to tobacco producing. This is always the picture in Chinese boletus (Yunnan) with high NIC amounts (1.0-5.0 mg/kg) and there is no difference between whole mushrooms and caps. That proved the thesis of Anastassiades and A. Fernandes-Alba. The contamination is from soil (and air).
- In European dried mushrooms, however, the cotinine and NIC levels were about the same with a maximum of 0.5 mg/kg. Their source is very probably the environmental tobacco smoke (ETS) or aging (oxidation) nicotine in the air. The amounts of NIC are significantly lower than in Chinese boletus. NIC Amounts in huts is higher than in the whole thallus. The source of the contamination is clear air only.
 Nicotine in dried porcini mushrooms: the cause of the stress must be clarified
Opinion 009/2009 of the BfR (German Federal Institute for Risk Assessment) of 28 February 2009
 Nikotin in Steinpilzen. Rückstand, Kontamination oder Artefakt? Hoenecke, K., Eurofins, oral presentation, meetig of the LChG (German food chemists association) am 2./3. April 2009
 Romanotto, Hoffmann, Gassert, Speer, Tobacco cultivation as a source of Nicotin load of Indian teas. Food Chemistry 2018; 72: 143-145
 M. Anastassiades, A. Fernandes-Alba, analysis of nicotine in Mushooms, oral presentation