Incidence of fungi and aflatoxins in imported areca nut samples
The carcinogenic, embryotoxic and immunotoxic properties of areca nuts are well documented. The nuts may also contain aflatoxins, but these have not been adequately quantified In products. The latter and the variable nut consumption pattern among chewers make estimations of exposure to aflatoxins and hence their contribution to the overall toxicity of the nut difficult. The aflatoxin content and incidence of fungi of boiled, baked and raw areca nut samples procured from different commercial outlets were determined. Only the raw, sliced nut samples contained aflatoxins B1, B2, G1 and G2 (3.5-26.2 μg kg-1). Forty per cent of these samples contained aflatoxin B1 in excess of the commonly accepted foodstuff limit of 5 μg kg-1. Based on areca nut consumption data of South African Indians, it was calculated that chewers of raw areca nut may be exposed to total aflatoxin (B1 + B2 + G1+ G2) quantities of 3.6-1080 ng per 24 h. Raw nut samples were relatively heavily contaminated with Aspergillus flavus, the counts of which corresponded with their aflatoxin content. Boiled nut samples harboured A. glaucus species which were not present on either baked or raw nuts. It was concluded that in such countries as India and Taiwan, chewers of raw areca may be exposed to concentrations of aflatoxins which may enhance the carcinogenic effects of these nuts on human tissues. It is unlikely, however, based on data regarding areca nut consumption among South African chewers, that the levels of aflatoxin on these nuts pose a health hazard.