Mycotoxin contamination of spices — An update

This update reviews studies since 1986 concerned with fungal infestation and mycotoxin occurrence in spices. Mycotoxins continue to pose a health concern via human exposure to contaminated spices. Reports indicated average mold counts in the assorted peppers examined to range from 200 to 3 400 000 mold spores g−1 substrate. Of 49% of A. flavus isolates found to be toxigenic, 79% produced aflatoxin B1 (AFB1). Another investigation found AFB1 levels in Coriander sativum in excess of 75 ppb. A sampling of commercial spices in Thailand revealed that 18% of samples of herbs and spices were contaminated with AFB1 (range 40–160 ppb). Among inhibitory ‘essential oils’ from several spices more resistant to mycotoxins, thymol isolated from thyme leaves was shown to inhibit both mycelial growth and aflatoxin production. Substantial reductions in fungal counts and near complete decomposition of AFB1 by irradiation have also been reported. Key future studies may explore irradiation methods, genetic engineering aimed at improving resistance to moulds, and limiting factors which allow mycotoxin production.