Transformation of paralytic shellfish poisoning toxins in Crassostrea gigas and Pecten maximus reference materials

► Comparison of incurred shellfish tissues with plankton-spiked tissues. ► Assessment of effects of gamma irradiation and chemical additives. ► Improved stability in incurred materials. ► Good stability of N-sulfocarbamoyl toxins. ► Epimerisation reduced in stabilised incurred tissues.