LINKS BETWEEN CASSAVA MARKETING, PROCESSING AND DIETARY CYANIDE EXPOSURE IN ZAIRE
In Zaire the naturally occurring cyanogenic glucosides in cassava roots are mainly removed before consumption by methods based on soaking followed by drying or heating. These methods effectively remove cyanogenic substances from cassava, and most have been used for several generations. The sequence and length of each step involved are part of the cultural heritage. However, outbreaks of the paralytic disease konzo in Bandundu region in Zaire have been attributed to high dietary cyanide exposure from consumption of insufficiently processed cassava roots. Field surveys using focus-group discussions, field observations and individual interviews revealed that women in the konzo-affected areas, when in a hurry to sell cassava roots, shorten the soaking period from the traditional three night to only one or two nights. A village-based processing experiment showed that apparently small changes in the sequence and length of pounding and sun-drying of short-soaked roots considerably increased the amounts of residual cyanogens in the flour consumed in the village. However, transportation of the short-soaked roots to the capital city Kinshasa and the subsequent use of mechanical milling by the urban population appear to secure a sufficient removal of cyanogens as indicated by low levels of the cyanide detoxification product thiocyanate in the urine of women in Kinshasa. These studies surprisingly show that a rapid increase of marketing of cassava in an area using defective processing methods may result in cyanide exposure among the rural communities that sell rather than among the urban population that buys the insufficiently processed roots.
Banea, M. and Rosling, H. (1994). LINKS BETWEEN CASSAVA MARKETING, PROCESSING AND DIETARY CYANIDE EXPOSURE IN ZAIRE. Acta Hortic. 375, 379-384
Konzo, processing modification, food intoxication, group interview