Chapter 12 - Mycotoxins and Product Safety

Abstract

Aflatoxin contamination impacts both the marketability and safety of peanuts as a food source worldwide. Regulations on allowable levels of aflatoxin reduce exposure in many countries, but in developing countries where food is scarce and regulations are not well enforced, populations are exposed to aflatoxin concentrations that can cause acute and chronic syndromes. Such syndromes include increased incidence of cancer, immunosuppression, stunting in children, and death in the most severe cases. Exposure occurs when peanuts or peanut products contaminated with aflatoxins are ingested. Contamination can occur when peanuts are infected in the field or in storage by certain species of fungi within Aspergillus section Flavi. Aspergillus flavus is the predominant aflatoxin producing species on peanut, but Aspergillus parasiticus is often present. These two species occupy overlapping ecological niches and respond similarly to control strategies. Aflatoxin B1 is the most toxic and carcinogenic of the aflatoxins produced by the two fungi. Aspergillus flavus also produces B2 and A. parasiticus produces B1, B2, G1, and G2. Management of aflatoxin contamination is difficult in the field and in storage. Environmental conditions greatly affect susceptibility of peanuts to the disease in the field. Resistance to aflatoxin contamination is heritable, and genotypes with some resistance have been identified; however, it has been difficult to achieve adequate levels of resistance under environmental conditions most favorable for aflatoxin contamination. Control of aflatoxin in storage resulting from either new infections occurring in storage or continued aflatoxin production from infection that occurred before the seeds went into storage also is challenging. The available genome sequences of Arachis ipaënsis and Arachis duranensis, the diploid progenitors of cultivated peanut, provide new resources to accelerate genomics-assisted breeding and the development of transgenic plants.