Are Boletoid Mushrooms Toxic?

It was reported earlier that few citizens felt unwell after consuming boletoid mushrooms imported from China. Some people may wonder, “Aren’t boletoid mushrooms edible?” The fact is that there are so many species of boletoid mushrooms, and some of them are toxic.

In China, 397 mushroom species belong to the family Boletaceae, of which only 33 species are toxic1. Since poisonous and non-poisonous species have similar morphological features, accidental harvesting and consumption of toxic boletoid mushrooms are not uncommon. Depending on the amount and species consumed, different mushroom poisoning symptoms may occur: (Testing)

Symptom

Example of

Toxic Boletoid Mushroom 2

Gastrointestinal Irritation

 

(e.g. nausea, persistent vomiting, abdominal cramps & diarrhoea)

Boletus badius

 

 

Photo: Wikipedia, 2005

https://en.wikipedia.org/wiki/Imleria_badia#/media/File:Boletus_badius_JPG1.jpg

Neurological symptom

Boletus satanas

 

Photo: Wikipedia, 2005

https://en.wikipedia.org/wiki/Rubroboletus_satanas#/media/File:Boletus_satanas.JPG

Hallucination

Boletus speciosus

 

Photo: Wikipedia, 2011

https://it.wikipedia.org/wiki/Boletus_speciosus#/media/File:Boletus_speciosus_var._brunneus_169906.jpg

Hemolysis symptom

Suillus luteus

 

 

Photo: Wikipedia, 2014

https://en.wikipedia.org/wiki/Suillus_luteus#/media/File:Suillus_luteus_475376.jpg

Liver Damage

Xanthoconium affine

 

 

Photo: Wikipedia, 2009

https://en.wikipedia.org/wiki/Xanthoconium_affine#/media/File:Xanthoconium_affine_55121.jpg

Source of Information

1孫亞軍 袁偉 劉倫光 張麗傑 施國慶 王啟興 一起有毒牛肝菌引起食物中毒的調查 [期刊論文] -中華流行病學雜誌 2012, 33(12)

2圖力古爾 包海鷹 李玉 中國毒蘑菇名錄 [研究論文] - 菌物學報 2014, 33(3):517-548

Mushroom Toxins

Although the toxin compositions within boletoid mushrooms are complicated, there are only a limited number of relevant studies. Examples of well characterized toxins include toxic proteins and hallucinogens. On the other hand, it is noted that the types and amounts of toxins within a mushroom could vary with time and its geographical location.

Chromatographic techniques (e.g. HPLC) can be used to check whether a boletoid mushroom contains the well characterized toxins. However, they are not ideal for identifying toxins of unknown chemical natures.

Mushroom Identification

As such, botanical identification is the most widely used method to tell whether a boletoid mushroom is toxic or not. This depends on the ability and experience of mushroom harvesters and merchandisers to identify toxic mushroom species.

The fact, however, is that incidents of mixing edible mushroom species with toxic ones still occur from time to time. This is because not all mushroom harvesters and merchandisers are well trained in species identification. Moreover, on occasion, different literatures have different stances on the toxicity of a species, this can lead to confusion.

In order to prevent accidental harvesting and importation of toxic mushroom species from happening, it is necessary to enhance public education and training. Moreover, mushroom identification should be done scientifically and objectively. Since molecular biotechnology is already well developed, many testing laboratories can rapidly and accurately identify the species of a boletoid mushroom through the gene sequence analysis.

 

by Food Safety Specialist

YY Tsang

 

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