Modeling maize aflatoxins and fumonisins in a Tanzanian smallholder system: Accounting for diverse risk factors improves mycotoxin models

PLoS One. 2025 Jan 13;20(1):e0316457. doi: 10.1371/journal.pone.0316457. eCollection 2025.

Abstract

Human exposure to mycotoxins is common and often severe in underregulated maize-based food systems. This study explored how monitoring of these systems could help to identify when and where outbreaks occur and inform potential mitigation efforts. Within a maize smallholder system in Kongwa District, Tanzania, we performed two food surveys of mycotoxin contamination at local grain mills, documenting high levels of aflatoxins and fumonisins in maize destined for human consumption. A farmer questionnaire documented diverse pre-harvest and post-harvest practices among smallholder farmers. We modeled maize aflatoxins and fumonisins as a function of diverse indicators of mycotoxin risk based on survey data, high-resolution geospatial environmental data (normalized difference vegetation index and soil quality), and proximal near-infrared spectroscopy. Interestingly, mixed linear models revealed that all data types explained some portion of variance in aflatoxin and fumonisin concentrations. Including all covariates, 2015 models explained 27.6% and 20.6% of variation in aflatoxin and fumonisin, and 2019 models explained 39.4% and 40.0% of variation in aflatoxin and fumonisin. This study demonstrates the value of using low-cost risk factors to model mycotoxins and provides a framework for designing and implementing mycotoxin monitoring within smallholder settings.

MeSH terms

  • Aflatoxins* / analysis
  • Food Contamination* / analysis
  • Fumonisins* / analysis
  • Humans
  • Mycotoxins / analysis
  • Risk Factors
  • Tanzania
  • Zea mays* / chemistry
  • Zea mays* / microbiology

Substances

  • Fumonisins
  • Aflatoxins
  • Mycotoxins

Grants and funding

Funding for this research was provided by the Mycotoxin Mitigation Trial (Grant No. OPP1155626) from the Bill & Melinda Gates Foundation (https://www.gatesfoundation.org/) (RJN). The McKnight Foundation Collaborative Crop Research Program (https://www.mcknight.org/) also supported this research (RJN). Key support for the 2019 survey was provided by the Cornell Atkinson Center for Sustainability Small Grants Program (https://www.atkinson.cornell.edu/), and by a travel grant from the Mario Einaudi Center for International Studies (https://einaudi.cornell.edu/) (WS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.