Ochratoxin A contamination and related high-yield toxin strains in Guizhou dried red chilies

Abstract

Dried red chili is an popular spice widely used in the world, but is vulnerable to be contaminated by toxigenic fungi, resulting in ochratoxin A contamination. The current study detected OTA contents in both chili peels (n = 49) and seeds (n = 49) of Guizhou dried red chilies. Results showed that 22.45% of chili peels and 34.70% of chili seeds exceeded the EU regulatory limit of OTA content (20 μg/kg), whereas the highest OTA level was up to 54.12 μg/kg in chili peels and 36.67 μg/kg in chili seeds. In total, 34 fungal strains were isolated from Guizhou dried red chilies with 9 of them had OTA-producing abilities, belonging to Penicillium chrysogenum (4 strains), Penicillium rubens (3 strains), Aspergillus niger (1 strain) and Aspergillus fumigatus (1 strain) by morphology and molecular techniques. In vitro and in vivo experiments identified A. niger DTZ-12 (GenBank accession number: ON383976) and P. chrysogenum DL-8 (GenBank accession number: ON383969) displayed the top 2 OTA-producing capacities with their own growth characteristics. In conclusion, it is urgent to take effective measures to prevent and control the OTA contamination in Guizhou dried red chilies. • Ochratoxin A levels in Guizhou dried red chilis ranged from non-detective to 54.12 μg/kg. • The OTA pollution in chili seeds was more serious than that in chili peels. • Aspergillus niger DTZ-12 and Penicillium chrysogenum DL-8 were top 2 high-yield OTA producer in Guizhou dried red chilies.