Aflatoxin Biocontrol Using Native Atoxigenic Aspergillus

Aflatoxins are highly toxic compounds produced by Aspergillus section Flavi fungi when they infect crops (e.g., maize, groundnut, tree nuts) before, during, or after harvest. Aflatoxin contamination negatively impacts human and animal health, food security, and trade sectors, particularly in the tropics and subtropics. Most aflatoxin contamination is caused by Aspergillus flavus. However, within this species there exist genotypes that cannot produce the toxins (i.e., atoxigenic). Because contamination often starts preharvest, integrated management strategies are needed from field to fork. Such strategies have been effective when centered on biocontrol using native atoxigenic isolates of A. flavus at the preharvest stage. Atoxigenic-based biocontrol was first developed and registered in the United States. Thereafter, the technology was adapted and registered in several African countries using native atoxigenic isolates. Subsequently, Italy, Pakistan, and Serbia developed products containing native atoxigenic isolates. Other countries are developing their own native, atoxigenic-based biocontrol products, and a few have evaluated products originally developed for use elsewhere. Native, widely distributed, competitive isolates belonging to atoxigenic vegetative compatibility groups are preferred for their greater chances of long-term establishment and high effectiveness, stronger in-country acceptance, and faster regulatory approval compared to exotic fungi. Across countries, farmer-led field trials and commercial usage have shown that treated crops contain significantly lower (usually >80% less) aflatoxin levels than untreated crops from neighboring fields. This article outlines pathways for sustainable development, testing, registration, and scaling of aflatoxin bioprotectants in several African countries to significantly contribute to improving food safety. Those long, arduous pathways rely on having multisectoral enabling environments, whose absence can stagnate the technology.