Screening of multi-class cyanotoxins in algal dietary supplements marketed in North America

Abstract

Algal dietary supplements are marketed for their health benefits and nutritional value. However, these types of products can be contaminated by toxins produced by co-occurring toxigenic cyanobacteria. In order to evaluate the contamination of different supplements available on the North American market, we purchased 37 samples of spirulina, Aphanizomenon flos-aquae, Chlorella and kelp, and analysed them for 27 cyanotoxins using liquid chromatography mass spectrometry methods (HPLC-MS/MS and HPLC-HRMS). We found microcystins (MC) in the 8 Aphanizomenon samples with levels up to 1000 ng g−1 dw and 2,4-diaminobutyric acid (DAB) in all samples with values ranging from 3 to 1600 ng g−1. Anatoxin-a (ANA) and β-amino-N-methylalanine (BAMA) were not detected, while other toxins were detected with no clear link to the nature of the alga. Considering these results, Aphanizomenon products may require stricter monitoring to prevent further contamination. The findings are also of interest to consumers so that they can properly assess the risks that may be involved in the regular consumption of certain algal dietary supplements.