Total cyanide content of cassava food products in Australia

• Published in: Journal of food composition and analysis Vol. 25; no. 1; pp. 79 - 82
• Main Authors: Burns, Anna E., Bradbury, J. Howard, Cavagnaro, Timothy R., Gleadow, Roslyn M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Inc 01.02.2012; Elsevier
• Subjects: Biological and medical sciences; Cassava; Cyanide; Cyanogenesis; Cyanogenic glucosides; Food analysis; Food composition; Food industries; Food processing; Food safety; Fundamental and applied biological sciences. Psychology; General aspects; Hygiene and safety; Manihot esculenta Crantz; Methods of analysis, processing and quality control, regulation, standards; Picrate method; Toxins; Australia; Oceania; Cyanide; Cyanogenesis; Picrate method; Toxins; Food safety; Food composition; Food processing; Cyanogenic glucosides; Food analysis; Manihot esculenta Crantz; Cassava; Manihot esculenta; Cyanides; Cyanogenic glucoside; Method; Toxin; Dicotyledones; Analysis; Angiospermae; Tuber; Euphorbiaceae; Spermatophyta; Food
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2011.06.005

► Unprocesssed cassava is cyanogenic and highly toxic. ► Cassava is increasingly exported to countries with little knowledge of toxicity risks. ► Samples from 2 cities before new Australian standards showed high cyanide levels. ► All vegetable chips before new Australian standards were toxic, some highly toxic. ► Tapioca and flour products were below the recommended limit 10ppm HCN. Cassava products obtained in two major Australian cities, Melbourne and Canberra, were analysed for total cyanide content using the picrate method. In Melbourne in 2010, ready to eat cassava chips were found to contain large amounts of cyanide with a mean value of 91mg HCN equivalents/kg fresh weight=ppm. In Canberra, similar values were found over a six-year study with cassava chip samples, except for one sample that gave 7ppm, which was obtained in 2011 after the introduction by Food Standards Australia and New Zealand of a 10ppm maximum limit. In Melbourne, the highest value obtained was 262ppm. A calculation based on this very high cyanide sample and using the lethal dose of cyanide for humans, shows that a child of 20kg body weight would only need to eat 40–270g of these chips to reach the lethal dose. Frozen cassava roots gave a mean value of 52ppm total cyanide, which is also a cause for concern. In contrast, more highly processed foods contained<1ppm total cyanide.