Tree nuts, aflatoxins

Mycotoxin contamination of foods may cause considerable economic losses. On a global perspective, aflatoxins in tree nuts, dry fruits, and spices, Fusarium toxins in cereals (particularly maize, wheat, and barley), and ochratoxin A in cereals and coffee are of major importance (Bhat and Vasanthi, 1999). Regional problems also may arise from mycotoxins in fruits such as patulin in apples, ochratoxin A in grapes and dried vine fruits, or aflatoxins in different dried fruits. 

In addition to peanuts (which are not botanically true nuts), aflatoxins have been found in many of the tree nuts including pistachios, almonds, pecans, and other tree nuts ( ). ... 

A. flavus invasion and aflatoxin development can occur in the absence of insect damage, results suggest that sound almond kernels are relatively free of aflatoxin contamination. However, surveys over a three-year period established that aflatoxin may occur in tree nuts, such as almond, throughout the growing area and that only a relatively few kernels in a large population were contaminated W ... 

Although A. flavus will grow on almost any natural or processed substrate, aflatoxin occurs naturally primarily in corn, peanuts, cottonseed, grain sorghum, tree nuts, millet, copra, and figs (34). Substrate factors must be involved in contamination, since it is limited to a relatively small number of agricultural commodities. The restricted access of zinc has been proposed as an explanation for the inability of A. flavus to elaborate aflatoxin in soybeans (35). The availability of zinc for aflatoxin biosynthesis appears to be blocked by the presence of phytic acid in soybeans (36). 

AFLATOXINS (INTAKE FROM TREE NUTS AND DRIED FIGS)... 

The Codex Committee on Food Additives and Contaminants at its thirty-eighth session (Codex Alimentarius Commission, 2006) requested that the Committee conduct a dietary exposure assessment for total aflatoxins (AFT) from consumption of tree nuts (ready-to-eat)—in particular, almonds, Brazil nuts, hazelnuts and pistachios—and analyse the impact on dietary exposure of hypothetical maximum limits (MLs) of 4, 8, 10 and 15 pg/kg with consideration of the overall dietary AFT exposure, including consumption of maize and groundnuts. An additional request was received by the Committee to take into account in its assessment an additional hypothetical ML of 20 pg/kg. 

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