Mycotoxin risk assessment for consumers of groundnut in domestic markets in Nigeria

- Diverse moulds were recovered from 97.6% of 84 groundnut samples from four AEZs.
- Ten mycotoxins and 48 other microbial metabolites were detected in the food samples.
- Aflatoxins reached 2000 μg/kg (mean: 216 μg/kg); 14-25% samples exceeded limits.
- High levels of aflatoxins were found in all CPA positive groundnut samples.
- Consumers of contaminated groundnuts may be at risk of liver cancer and other combinatory effects.

The fungal and multi-mycotoxin profiles of groundnuts sold in domestic markets in Nigeria as well as the associated risk to consumers were assessed in the present study. Four hundred fungal isolates representing mainly Aspergillus [58.6%: Aspergillus section Flavi (37.1%) and A. niger-clade (21.5%)], Penicillium (40.9%) and Fusarium (0.5%) were isolated from 82 (97.6%, n = 84) groundnut samples collected from four agro-ecological zones (AEZs) of Nigeria. The incidence of aflatoxin-producing A. flavus isolates (71%) was significantly (p < 0.05) higher in the groundnuts than that of the non-aflatoxigenic isolates (29%). Fifty-four fungal metabolites [including aflatoxins (AFB1, AFB2, AFG1, AFG2 and AFM1), beauvericin (BEAU), cyclopiazonic acid (CPA), moniliformin, nivalenol and ochratoxin A] and four bacterial metabolites were detected in the groundnuts by liquid chromatography tandem mass spectrometry. Aflatoxins (39%; max: 2076 μg/kg; mean: 216 μg/kg) were detected in more samples than any other mycotoxin. About 25, 23 and 14% of the samples respectively were above the 2 μg/kg AFB1, 4 and 20 μg/kg total aflatoxin limits of the European Union and US FDA respectively. The mean margins of exposure of AFB1 and total aflatoxins for adult consumers were 1665 and 908, respectively, while mean estimated daily intake values for infants, children and adults were < 0.1% for BEAU and 4% for CPA. Consumers of mycotoxin contaminated groundnuts in Nigeria may therefore be at a risk of liver cancer in addition to other combinatory effects of mycotoxin/metabolite cocktails. There is need for increased targeted interventions in the groundnut value chain in Nigeria for public health benefits.