Fungal and aflatoxin contamination of marketed spices

Abstract

Fourteen spice samples were collected from local markets in Doha, Qatar, during 2012, and were surveyed for the presence of potentially harmful mycoflora and for contamination with aflatoxins B1, B2, G1, and G2 by high-performance liquid chromatography (HPLC). Among the tested spice samples, chili powder showed the highest presence of fungal propagules, while ginger, curry and garlic samples did not present any fungal contamination. A total of 120 isolates, mostly belonging to Aspergillus and Penicillium genera, were collected and 33 representative species were identified by amplification and sequencing of the internal transcribed spacer (ITS) region. Aspergillus flavus, Aspergillus nomius and Aspergillus niger were the most dominant. Thirty-seven Aspergillus strains were screened for their potential to produce aflatoxins using biochemical and molecular tools: only 9 A. flavus strains showed both fluorescence and amplification with all the three primers targeting aflP, aflM and aflR genes. Aflatoxins were detected in five spices (black pepper, chili, tandoori masala. turmeric and garam masala), and with the exception of garam masala, the tested samples of turmeric, black pepper, tandoori masala and chili powder exceeded B1 and/or total aflatoxin maximum levels. Our results demonstrate the potential for mycotoxin biosynthesis by fungi contaminating imported spice products.