Nuts, aflatoxin contamination

Aflatoxins have been detected in milk, cheese, corn and other cereals, peanuts, cottonseed, nuts, figs and other foodstuffs. Milk and milk products, eggs and meat products are sometimes contaminated (generally with aflatoxins Ml and M2) because of the animals consumption of aflatoxin-contaminated feed. 

Storage of pistachio nuts in the hull necessitates rewetting before dehulling therefore, storage of nuts after dehulling would provide less opportunity for aflatoxin contamination. Also, the presence of the hull favors mold growth under favorable conditions (7). 

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 ... 

Campbell, B.C., Molyneux, R.J. Schatzki, T.F. (2005) Advances in reducing aflatoxin contamination of U.S. tree nuts. In Abbas, H.K., ed. Aflatoxin and food safety. Boca Raton, FL, USA, CRC Press, Taylor Francis Group, pp. 483-515. 

Secretariat of I ran Codex Committee on Contaminants in Food (2007) Report submitted to the JECFA Secretariat on the frequency distribution and extent of aflatoxin contamination in Iranian pistachios nuts (in-shell), March. 

There are many other well established mycotoxicoses in farm animals in different parts of the world, but one group of metabolites is of particular importance because they are carcinogenic to some animal species. The aflatoxins, produced by Aspergillusflavus and A. parasiticus, first came into prominence because they were responsible for the deaths of large numbers of turkey poults on British farms. The turkey poults were being fed on pelleted feed, a major constituent of which was ground-nut meal contaminated with aflatoxins. Turkey poults, ducklings and chickens are all particularly sensitive to the acute... 

Principal commodities susceptible to aflatoxin contamination are ground nuts, treenuts, cottonseed, and grains, particularly corn. Aflatoxin contamination is a worldwide problem, especially in tropical and subtropical countries where high humidity year round... 

Pea.nuts, The proteins of peanuts are low in lysine, threonine, cystine plus methionine, and tryptophan when compared to the amino acid requirements for children but meet the requirements for adults (see Table 3). Peanut flour can be used to increase the nutritive value of cereals such as cornmeal but further improvement is noted by the addition of lysine (71). The trypsin inhibitor content of raw peanuts is about one-fifth that of raw soybeans, but this concentration is sufficient to cause hypertrophy (enlargement) of the pancreas in rats. The inhibitors of peanuts are largely inactivated by moist heat treatment (48). As for cottonseed, peanuts are prone to contamination by aflatoxin. FDA regulations limit aflatoxin levels of peanuts and meals to 100 ppb for breeding beef catde, breeding swine, or poultry 200 ppb for finishing swine 300 ppb for finishing beef catde 20 ppb for immature animals and dairy animals and 20 ppb for humans. 

The aflatoxins are rather unpleasant fungal toxins. At high levels they can cause severe liver damage in animals and humans, and at lower levels they are implicated in liver cancer. These toxins are produced by the fungus Aspergillus flavus, a common contaminant on nuts and grains. Aflatoxin Bi is the most commonly encountered... 

Health status and age, both young and old, also influence the response. Aflatoxin from contaminated nuts has a greater likelihood of causing cancer in someone with a liver disease such as hepatitis. It is important to develop a knowledge of which plants and animals can be dangerous and learn how to avoid dangerous contact with them. 

Fig. 4 Typical chromatogram of aflatoxins B, B2, G, and G2 naturally contaminated pistachio nuts sample. Aflatoxin B, (AFB1) 0.75 fig/kg, aflatoxin B2 (AFB2) 0.12 fig/kg, aflatoxin G] (AFGl) 0.68 fig/kg, and aflatoxin G2 (AFG2) 0.15 /rg/kg. Mobile phase water methanol acetonitrile 54 29 17. Pump A regulated at 1 ml/min Pump B (postcolumn derivatization with bromine) regulated at 0.4 ml/min.

Fungal mycotoxins, including aflatoxin Bi derived from Aspergillus flavus, contaminate cereals, grains, and nuts, and aflatoxin Bj ingestion is correlated with a high incidence of liver cancer in animal models and humans. Aflatoxins are heterocyclic and contain several endocyclic oxygen molecules. They are... 

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. 

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). 

Some symptoms of acute aflatoxicosis in humans arising from ingestion of contaminated nuts are vomiting, abdominal pain, and pulmonary edema. High exposure can cause convulsions, coma and death. The oral LD50 value of aflatoxin B1 in humans is estimated to be 4 mg/kg. 

Several studies have described the production of antibodies to toxins, that are capable of detecting very small quantities of contaminants, such as aflatoxins in grain and nut products [37-39] and shellfish poisoning toxins [40,41]. 

---