Pistachios, aflatoxin

Methanol-water is the extraction medium of the method recently tested for validation by the European Commission (39), for the determination of aflatoxins at the European regulatory limits for dried figs, pistachios, peanut butter, and paprika 50 g of the test portion are extracted with methanol-water (80 20) for dried figs and paprika, and methanol-water (80 20) plus 100 ml of hexane for peanut butter and pistachio. After filtration, the filtrate is added to phosphate buffer saline (PBS) for the purification step. 

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.

Method. The sample is spotted on to a TLC plate (silica gel) followed by 2 d of a solution of TFA (50% in chloroform, prepared fresh each day). The reaction is allowed to proceed for 5 min, after which time the plate is dried with a stream of nitrogen or air. The plate is then developed with chloroform—acetone (in various ratios such as 9 1 or 4 1), benzene-ethanol-water (43 35 19) or ethyl acetate-methanol-water (96 3 1). The plate is removed from the tank and dried in the dark. The spots are observed visually under UV light at long wavelength. The derivative of aflatoxin Bt appears blue, while the derivative of aflatoxin Gi is green. This confirmation technique has been applied to peanuts, brazil nuts, pistachio nuts, walnuts, barley, corn and other foods. 

Work Item H determination of aflatoxin Bi and total aflatoxins by immunoaffinity column clean-up and HPLC in fig paste, pistachios, peanut butter and paprika powder. 

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 ( ). ... 

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). 

Black walnut cultivars Rawlins and Thomas had considerably lower gallic acid levels of -1% dw, quite close to that of the pistachio cultivar Kerman (0.5% dw), and in vitro aflatoxin production for the walnut Thomas and pistachio Kerman were also similar at 45 and 40 J,g/plate, respectively [17], The hydrolysable tannin in pistachios has a core of quinic acid, rather than glucose (unpublished results), and its stereochemistry is such that dimerization of gallic acid moieties to hexahy-droxydiphenic esters, and consequent formation of ellagic acid, cannot occur. Any aflatoxin inhibitory activity is, therefore, dependent on either the tannin itself or gallic acid. 

In contrast to walnuts and pistachios, almond pellicle contains no hydrolysable tannin and therefore no gallic acid was detectable in the cultivars Nonpareil and Mission. This is consistent with their propensity to accumulate aflatoxins [9] and their ability to support aflatoxin biosynthesis. However, there are considerable differences in aflatoxin production in vitro between cultivars and these must be due to compounds other than hydrolysable tannins. Almond pellicle has been shown to contain other phenolic constituents, primarily phenolic acids and flavonoids, which may suppress aflatoxin production although less effectively than the tannins [27-29],... 

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. 

Aghamohammadi, M., Hashemi, J., Kram, G.A. Alizadeh, N. (2007) Enhanced synchronous spectrofluorimetric determination of aflatoxin B1 in pistachio samples using multivariate analysis. Anal. Chim. Acta 582, 288-294. 

AOAC International (2000a) Aflatoxin B1 and total aflatoxins in peanut butter, pistachio paste, tig paste, and paprika powder immunoaffinity column-liquid chromatography with postcolumn derivatization. In Official methods of analysis of AOAC International, 17th ed. Gaithersburg, MD, USA, AOAC International (AOAC Method 999.07). 

Campbell, B.C., Molyneux, R.J. Schatzki, T.F. (2003) Current research on reducing pre-and post-harvest aflatoxin contamination of U.S. almond, pistachio, and walnut. J. Toxicol. Toxin Rev. 22(2-3), 225-266. 

Codex Committee on Contaminants in Food (2007) CX/CF 07/1/9. Discussion paper on maximum levels for total aflatoxins in ready-to-eat almonds, hazelnuts and pistachios. Rome, Italy, Joint FAO/WHO Food Standards Programme, Codex Committee on Contaminants in Food (ftp //ftp.fao.org/Codex/cccf1/cf01 09e.pdf). 

Doster, M.A. Michaiiides, T.J. (1994) Aspeiy/Z/us molds and aflatoxins in pistachio nuts in California. Phytopathology 8A, 583-590. 

Fooladi, M.H. Farahnaky, A. (2003) Aflatoxin removal from pistachio nuts by natural natrolite. J. Food Sci. 68, 1225-1228. 

Institute of Standards and Industrial Research of Iran (2000) Code of practice for sampling of pistachio and pistachio kernel for aflatoxin analysis. Islamic Republic of Iran, Institute of Standards and Industrial Research of Iran (ISIRI 5197). 

Lee, N.A., Wang, S., Allan, R.D. Kennedy, I.R. (2004) A rapid aflatoxin B1 ELISA development and validation with reduced matrix effects for peanuts, com, pistachio, and soybeans. J. Agric. Food Chem. 52, 2746-2755. 

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. 

Trucksess, M.W., Stack, M.E., Stanley, N., Albert, R.H. Romer, T.R. (1994) Multifunctional column coupled with liquid chromatography for determination of aflatoxins B1, B2, G1 and G2 in com, almonds, Brazil nuts, peanuts, and pistachio nuts collaborative study. J. AOAC lnt.77, 1512-1521. 

World Health Organization (2006) GEMS/Food Consumption Cluster Diets. Geneva, Department of Food Safety, Zoonoses and Foodborne Diseases, Revision August. Yazdanpanah, H., MohammadI, T., Abouhossain, G.A. Cheraghall, M. (2005) Effect of roasting on degradation of aflatoxins In contaminated pistachio nuts. Food Chem. Toxicol. 43, 1135-1139. 

A last example of IMS methods applied to food quality is the determination of aflatoxins B1 and B2 on pistachio samples methanol extracts of samples were introduced into an IMS analyzer equipped with an IMS equipped with a nonradioactive, corona discharge ion source. The response to aflatoxins was acceptable for screening purposes, with a linear range of roughly 100, relative standard deviations 10% or lower, and a limit of detection of 0.25 ng for both aflatoxins. Ammonia could be used as a dopant, and detection limits were improved by a factor of 2.5. Authentic pistachio samples were analyzed without difficulties. 

In the case of aflatoxins, detailed methods will vary from one commodity to another. Thus, defatted hazel nuts, pistachios, Brazil nuts, groundnuts, or groundnut meal, can be extracted directly with chloroform after the addition of a small volume of water, whereas cottonseed and cottonseed products are best extracted initially with aqueous acetone and the aflatoxins subsequently partitioned into chloroform. Established procedures for aflatoxins that illustrate these principles include ... 

Aflatoxins in corn - TLC method 974.16 Aflatoxins in pistachio nuts - TLC method... 

Aflatoxins Bl, B2, G1, G2 1 Groundnuts, peanuts, tree nuts, shell-fruits (pistachios, nuts), maize, figs, dried raisins, spices Aspergillus flavus A. parasiticus... 

Aflatoxins B and G in peanut butter, pistachios, fig paste, and paprika Methanol 80% and defatting with pure hexane Immunoaffinity cleanup prior to LC coupled to fluorescence detector and postcolumn derivatization by using iodination or bromination 0.2 ng per kg of aflatoxin B1 0.4 pg per kg for sum of aflatoxins B and G 85-100... 

Aflatoxin in food is one of the most widely spread food contaminations. It can be found in over a hundred kinds of agro-products and foods, snch as peanuts, com, rice, soy sauce, vinegar, plant oil, pistachios, tea, Chinese medicinal herb, eggs, milk, feed, and so on. Some have also been detected in animal organisms. Besides... 

---