Pyrrolizidine alkaloids in food and phytomedicine: Occurrence, exposure, toxicity, mechanisms, and risk assessment-A review - Schrenk, D; Gao, L; Lin, G; Mahony, C; Mulder, P P; Peijnenburg, A; Pfuhler, S; Rietjens, I M; Rutz, L; Steinhoff, B (Food Chem Toxicol, 2020)