Removal of Aflatoxins from Cassava Roots: Studies on Dry Fermentation and Micro-ferment in Rural Democratic Republic of Congo

Aims: The main objective of this study is to inhibit the production of aflatoxins during the dry fermentation of cassava. To do this, we substituted the traditional ferment with a pure culture biomass of Rhizopus oryzae used as a starter (micro ferment).

Study Design: Six successive replications, in controlled fermentation and uncontrolled fermentation, in a peasant environment (Beni, North Kivu) and fermentation directed by the strain of R. oryzae were carried out.

Place and Duration of Study: A total of 57 samples were collected from the local markets in 18 sites in North Kivu, Democratic Republic of Congo and 36 samples were obtained from the experimental fermentation with the R. oryzae strain between March and April 2018.

Methodology: The levels of aflatoxin were determined by biological detection and spectrophotometric assay. For biological detection, aflatoxins were detected by inhibiting the growth of sensitive E. coli C600 on nutrient agar following their diffusion. The aflatoxin assay was done by the rapid multitoxin assay method using the Acquity Spectrophotometer HPTLC and the Quattro Preparier XE mass spectrophotometric at South Africa's Perishable Products Export Control Board (PPECB) (RSA).

Results: The results of the assay revealed an absence of aflatoxins in cassava fermented by scrapings from fermentation led by R. oryzea, while the non-directed fermentation controls were all contaminated with aflatoxins.

Conclusion: These results show that it is possible to prevent the production of aflatoxins in cassava during fermentation when an aflatoxin-inhibiting microbial biomass is used which can progressively invade and colonize the fermentation site and thereby control the fermentation activities of cassava.