Cyanogenic potential of fresh and frozen cassava on retail sale in three Irish cities: a snapshot survey

Summary Imported cassava roots can be found on retail sale in several I rish cities and towns. Fresh roots ( n  = 36 roots) and peeled frozen root pieces ( n  = 28 packs) were randomly purchased from five retailers in Belfast, Dublin and Limerick and assayed for cyanogenic potential ( CN p). Total CN p of fresh root parenchyma varied from 37.5 to 242.9 mg kg −1 as HCN , dry weight basis – dwb), averaging 104.4 mg kg −1 HCN (dwb). Total CN p of frozen root parenchyma ( n  = 28 packs) ranged from 28.5 to 258.6 mg kg −1 HCN (dwb), averaging 81.7 mg kg −1 HCN (dwb). Around 78% of fresh roots, and 93% of packs of frozen parenchyma, complied with the Codex Alimentarius definition of ‘sweet’ cassava, but most (86.1% and 64.3%, respectively) exceeded European Union NETTOX recommendations for total CN p. In around one‐third of frozen parenchyma packs, nonglycosidic cyanogens accounted for 83–100% of total CN p. The toxicological implications are briefly discussed.