Mycobiota and aflatoxin B1 contamination of Piper guineense (Ashanti pepper), P. nigrum L. (black pepper) and Monodora myristica (calabash nutmeg) from Lagos, Nigeria

The incidence of moulds including toxigenic Aspergillus section Flavi, and aflatoxin B1 (AFB1) were determined in 36 samples of three spices. Moulds were isolated and characterized by conventional mycological techniques while AFB1 was analyzed by Thin-layer chromatography with fluorescent detection coupled with an immunoaffinity clean up step. About 67% (24 out of 36) of the spices were contaminated by moulds belonging to four genera: Aspergillus, Fusarium, Penicillium and Rhizopus. Aspergillus was the most predominant (78.9%) genera and a total of 220 Aspergillus section Flavi isolates were obtained. The incidence of A. flavus (63.2%) was higher than that of A. tamarii (36.8%). Approximately, 68% of A. flavus isolates from the spices produced aflatoxins in neutral red desiccated coconut agar (NRDCA). Only 19.4% of the spices were contaminated with AFB1 and the concentrations in 8.3% of calabash nutmeg exceeded the NAFDAC permissible limit of 20 μg/kg aflatoxin in foods in Nigeria. Of the three spices, calabash nutmeg showed the highest significant (p 0.05) mould count (3.45 Log10CFU), incidence of toxigenic Aspergillus section Flavi (50%) and AFB1 (50%). Spices especially calabash nutmeg are prone to contamination by moulds including toxigenic Aspergillus. Consequently, the risk of aflatoxicosis may be high and as such may threaten public health safety due to regular consumption of the spices though aflatoxin levels were low.