The cassava processing technique discussed by Howard Bradbury is an extremely valuable tool for detoxifying cassava, thereby helping to ensure that cassava is safe to consume.
We recently found that levels of cyanogens in the leaves and tubers of cassava can higher under drought conditions (vandergeer et al, 2012). The increased incidence of konzo (due to excess consumption of cyanogens) during times of drought may be explained by the increased cyanogen concentrations in the plants. It may also be due to increased cassava consumption due to the failure of other less drought tolerant crops and/or decreased availability of water for the detoxification of cassava foodstuffs. Consequently, efforts promoting cassava as a suitable crop in areas likely to become drier with climate change must be accompanied by development activities that help to ensure that growers of cassava are aware of the need for, and appropriate methods to, detoxify cassava.
These issues are discussed further in the following references:
1. van der Geer R, Miller RE, Bain, M, Gleadow, RM, Cavagnaro TR. (2013). Drought adversely affects tuber development and nutritional quality of the staple crop cassava (Manihot esculenta Crantz). Functional Plant Biology. 40: 195-200.
2. Burns A, Gleadow RM, Cliff J, Zacarias A, Cavagnaro TR. (2010). Cassava: the drought, war and famine crop in a changing world. Sustainability. 2: 3572-3607.