Quantitative analysis of the Tricholoma ustale-derived toxin, ustalic acid, in mushroom and food samples by LC-MS/MS.

Tricholoma ustale, a poisonous member of the Tricholomataceae family, causes gastrointestinal symptoms such as diarrhea and vomiting. In Japan, 86 cases (affecting a total of 347 patients) of poisoning with Tricholoma ustale have been reported between 1989 and 2010. Ustalic acid is one of the primary toxic components in Tricholoma ustale.