Cassava processing, consumption, and cyanide toxicity.

The frequency of cassava consumption was investigated among three groups of people representing students from traditional and nontraditional cassava-consuming environments and cassava processors. Of these, 64% of the students at Obafemi Awolowo University, Ile-Ife, 38% of those at the Federal University of Technology, Akure, and 44% of the cassava processors consumed cassava products at least once a day, while 4, 35, and 28% of the groups, respectively, were moderate consumers (4-6 times a week). The serum thiocyanate level of the processors was significantly higher (0.57 mg/dl) than those of the students (0.38 mg/dl), but there was no significant difference in the urinary thiocyanate level of the three groups. Analysis of cassava and its intermediate and final products for free cyanide, acetone cyanohydrin, and intact glucosides during the production of such cassava products as gari, fufu, and lafun revealed that while the finished products might be safe for human consumption, the workers were probably exposed at different stages of processing to nondietary sources of cyanide.