Combined LC-MS and qPCR Analysis of Authentic Cumin Samples to Identify the Botanical Origin of Their Pyrrolizidine Alkaloid Contamination

Pyrrolizidine alkaloids (PAs) and tropane alkaloids (TAs) are toxins that naturally occur in plants worldwide and can contaminate food such as (herbal) teas, culinary herbs, and spices if these plants are unintendedly coharvested. Cumin has been identified as a particularly problematic matrix regarding PA contamination, frequently exceeding the European Union (EU) regulatory limits. However, the botanical causes of PA contamination in cumin remain largely unknown. In the current study, 74 authentic cumin samples provided by vendors were analyzed for PAs and TAs using LC-MS and screened for PA-producing plants using qPCR. Analytes were detected in all samples, with 18 exceeding the EU regulatory PA limit. The identified PAs predominantly matched those typically found in European heliotrope (Heliotropium europaeum). However, qPCR did not detect known PA- or TA-producing plants and therefore did not align with the LC-MS findings. The clear indication of a specific plant responsible for PA contamination in cumin could help manufacturers improve weed control and minimize product contamination in the future.