There is no scientific basis for the claim that how long the fungus is soaked will cause toxicity.
Generally speaking, the fungus itself is non-toxic, under normal circumstances, qualified dry fungus after soaking, fried and blanched cold to eat are no problem. The reason why there will be “poisoning” phenomenon, may be due to soaking environment, temperature and other reasons lead to the fungus by microbial contamination, or fungus itself deteriorated and moldy.
Fungus is a high nutritional value of food, per 100g of fungus contains carbohydrates 65.6g, crude fiber 29.9g, protein 12.1g, can add some nutrients for the human body.
In short, the fungus itself is not toxic, soak how long will cause toxicity does not have a solid basis. Therefore, in order to safely consume fungus, should avoid long time soaking fungus. In addition, attention should be paid to a balanced diet, fungus can be combined with meat, vegetables, in order to prevent the body nutrient deficiency.