Contamination of common spices by aflatoxigenic fungi and aflatoxin B1 in Algeria

Abstract

Spices are usually produced in areas where the climatic conditions are favourable to growth of toxigenic fungi and production of mycotoxins. This study assesses the occurrence of aflatoxigenic fungi and aflatoxin B1 (AFB1) in spices marketed in Algeria. A total of 44 spice samples (4 for each type of spice) composed of aniseed, black pepper, caraway, cinnamon, coriander, cumin, ginger, red pepper, saffron, sweet cumin, and sweet pepper were collected from four popular markets located in Algeria. Mycological analysis of the spice was by dilution plating while AFB1 contamination levels were determined by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) after post-column derivatisation. The commonly isolated fungi were species of Aspergillus (56.4%), Penicillium (25.1%), Mucor (12.8%) and Eurotium (5.7%). Species belonging to Aspergillus section Flavi represented 28.9% of the total Aspergilli. The aflatoxin producing ability of isolates belonging to Aspergillus section Flavi was determined on coconut agar medium and confirmed by thin layer chromatography and HPLC-FLD. Ninety-four isolates (38.4%) of the 245 Aspergillus section Flavi examined produced aflatoxins. The most frequent chemotypes (84%) correspond to isolates able to produce both aflatoxin B and cyclopiazonic acid followed by the producers of only aflatoxin B. Twenty-three (63.9%) of the 36 spices contained AFB1 at levels ranging from 0.10 to 26.50 μg/kg. Two saffron (24.34 and 26.50 μg/kg) and two sweet cumin (14.65 and 19.07 μg/kg) samples were above the Algerian regulatory limit of 10 μg/kg. This work represents the first report about the occurrence of aflatoxigenic fungi and AFB1 in the common spices in Algeria.