Low cyanide exposure from consumption of cassava in Dar es Salaam, Tanzania.

The extent of cyanide exposure from cassava consumption was studied in low income suburbs of Dar es Salaam, Tanzania. Mean cyanogen levels in sun-dried root pieces called makopa was 9.4 (range 0-79) mg HCN equivalents kg(-1) dry weight. The mean glucoside and hydrogen cyanide levels were 6.4 and 3.2 mg HCN equivalents kg(-1) dry weight, respectively, while cyanohydrins were lower with a mean of 2.0 (range 0-27) equivalents kg(-1) dry weight. Food frequency interviews with 193 schoolchildren revealed that 13% of the children consumed cassava stiff porridge in the previous week. Fried cassava pieces were consumed by 82% and boiled cassava pieces by 49% of the children. The urinary thiocyanate in these children was 36 +/- 3 (mean +/- SEM) micromol l(-1) and mean urinary linamarin level was 18 +/- 1 micromol l(-1), indicating low cyanide exposure. Multiple regression analysis revealed a positive correlation between urinary thiocyanate and consumption of boiled cassava pieces as well as between urinary linamarin levels and daily intake of fried cassava pieces.