In the early 1960s more than 100,000 turkeys died in Britain of cancer of the liver. Eventually, researchers identified mouldy peanut flour from Brazil containing large amounts of aflatoxin as the cause of this mysterious 'turkey X' disease. Even today the toxin is regarded as one of the most virulent natural carcinogenic substances.
The tasteless toxin is produced by the mould aspergillus flavus. It grows in hot, arid regions, in the south-west of the US and in many regions of Africa and Asia. In Third World countries, particularly, this dangerous paintbrush-shaped mould is ubiquitous. This may be one reason for the high rate of liver cancer in Africa. "Our colleagues from the IITA in Nigeria recently succeeded in proving that 99 out of 100 children from Benin and Togo had aflatoxin in their blood," Professor Richard Sikora of the Bonn Institute of Plant Diseases explains. "The consequence is drastic impairment of growth and of other types of development."
'Good' mould displaces its highly toxic cousin
The remedy may lie in the idea of US researchers Dr. Peter J. Cotty, which is both simple and ingenious. "In addition to the dangerous strain aspergillus flavus there are also others which cannot produce any toxin," the Bonn plant pathologist Dr. Sebastian Kiewnick explains. "Cotty propagated this non-toxic strain of aspergillus on grains of corn and spread the mould-infected grains in fields of cotton. As a result, the non-toxic strain was present in substantially larger amounts and was thus able to almost entirely supplant the toxic variety." The success was overwhelming: aflatoxin infection of the cotton cobs dropped from an average of 1,000 ppb (parts per billion) to below 20 ppb, thereby lying within the US safety limit for animal food cotton seeds serve as food e.g. for dairy cattle.