A rapid HPLC post-column reaction analysis for the quantification of ergothioneine in edible mushrooms and in animals fed a diet supplemented with extracts from the processing waste of cultivated mushrooms

► A rapid HPLC post-column reaction assay methodology was developed for quantification of ergothioneine. ► The sensitivity and reproducibility of the method was similar to that of ESI mass spectrometry. ► The method is applicable for the quantitative analyses of ergothioneine in biological samples.