Occurrence of Aflatoxins in Rice Intended for Infant Flour Production in Ouagadougou, Burkina Faso

A total of four samples of rice intended for infant flour production in Ouagadougou were received at the Physico-chemistry laboratory of Food Technology Department (DTA) for quality control. The latter were also tested for Aspergillus section Flavi presence and analyzed for aflatoxins B1, B2, G1 and G2 content using high performance liquid chromatography (HPLC). Among the twenty (20) strains of mold isolated from these samples, three Aspergillus section Flavi were obtained and cultivated in “Aspergillus flavus and parasiticus Agar (AFPA)” to ascertain if they belong to Aspergillus flavus or Aspergillus parasiticus species. The qualitative ability of aflatoxin production was also performed by fluorescence emission under ultra violet light at 365 nm after four days of incubation at 30 °C on Coconut Agar Medium (CAM). Statistical analysis results showed that 75% of samples were contaminated with total aflatoxins (AFs) with contents ranging from 0.54 ± 0.06 to 2.40 ± 0.07 µg/Kg. Aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) were detected in two contaminated samples. AFB1 had the highest concentration as compared with other aflatoxins. A significant level of contamination (p< 0.0001) was observed in sample R441 compared to other sample types.

The Role of Aflatoxins in Aspergillus flavus Resistance to Stress

Aspergillus section Flavi produce the aflatoxins, secondary metabolites toxic to humans and animals. Why do these fungi produce aflatoxins? They do not have a clear role in pathogenicity or in niche competition. Aspergillus employs a considerable amount of energy to synthesize them: more than 20 enzymatic catalyzes are needed. Within the A. flavus species, all opportunistic pathogens of maize, more than half of the natural population are atoxigenic, indicating that aflatoxins are not so obviously linked to an enhancement of population fitness. The perspective changes in A. parasiticus, pathogen to peanuts, where more than 90% of the natural population produce the four aflatoxins. In this chapter, we aim to discuss our recent hypothesis that aflatoxins act as antioxidants providing more time to Aspergillus to “escape” an exploited substrate, that in the meanwhile is “fully charged” with reactive oxygen species and oxylipins.