ENVIRONMENTAL AND NUTRITIONAL FACTORS CONTROLLING AFLATOXIN PRODUCTION IN CASSAVA SOLID-STATE FERMENTATION

A physiological study of Aspergillus parasiticus on cassava solid state fermentation was performed to evaluate the risks of aflatoxin (AT) contamination of the cassava protein enrichment process with Aspergillus niger. The effects of key environmental (temperature, initial moisture content, aeration rate), nutritional (nitrogen and phosphorous source concentration) and ecological (mixed cultures using A. niger and different amounts of A. parasiticus) factors on aflatoxin production by A. parasiticus in this culture system were evaluated. It was found that A. parasiticus can grow and produce aflatoxins in this system. However, the operation temperature of the protein enrichment process (35°C) drastically reduces potential toxin production. Although N and P concentrations in the medium are partially inhibitory for AT biosynthesis, very high production can be attained anyway. The best toxicological protection was the strain itself (A. niger no. 10). When these two species grew together in solid state fermentation, aflatoxin production was completely inhibited. © 1990.