Applications aflatoxin

The two examples of sample preparation of solids containing low concentrations of the substances of interest will be the analysis of aflatoxins in corn meal (7) and the determination of the fungicide thiabendazole in citrus fruits. It should be pointed out that the applications chosen in this section attempt to reflect a range of analyses that the analyst is likely to meet in both research and industrial laboratories. 

Other preharvest techniques include the development of more resistant crops (e.g., Becker, 1999 Guo et al., 1998), and biological control with atoxigenic A. flavus strains (Cotty, 1990 Dorner et al., 1998). Atoxigenic A. jiavus competed successfully with a toxic isolate when they were grown in mixed culture, obtaining a reduction of the aflatoxin content by 82 to 100%. This is a worthwhile approach for control, however possible side effects caused by a preemptive application of A. jiavus in the environment must be studied to determine potential risks to human and animal health. 

An interesting application of unsaturated diols 460 is the preparation of substituted perhydrofurofurans 463, a heterobicyclic core, present in families of naturally occurring products, such as aflatoxines ° . Hydroboration of diols 460 with BH3 in THE at 0°C... 

Application of relative activity factors to aflatoxin b, mutagenicity data prediction of... 

HPLC analysis of polycyclic aromatic hydrocarbons (PAH) in drinking water is one of the current and classical applications of fluorescence. In this case, the detector contains a fluorescence flow cell placed after the chromatographic column. This mode of detection is specifically adapted to obtain threshold measurements imposed by legislation. The same process allows the measurement of aflatoxins (Fig. 12.11) and many other organic compounds (such as adrenaline, quinine, steroids and vitamins). 

Enzyme-linked immunosorbent assay (ELISA) is a very useful technique for the specific and sensitive assay of certain compounds, in which suitable antibodies, monoclonal or polyclonal, to the compounds are available. The technique has found particular application m the monitoring of environmental contaminants and toxins, either studying the primarily contaminated materials, e.g., foodstuffs, or body fluids of potentially exposed humans. The technique has been increasingly applied to monitoring the carcinogenic mycotoxins, the aflatoxins. 

Recently, in many demanding sample preparation situations, more selective sorbents have been used. Affinity type sorbents, particularly immunosorbents, have gained popularity in trace analysis, not only for biological macromolecules but also for small molecules, like aflatoxins. MIPs have properties resembling those of affinity phases and therefore they may find unique applications where other sample pretreatment methods are tedious. This relates both to the separation of a single analyte and to the separation of a group of related analytes from the sample matrix. 

DRAGACCI s and FREMY J M (1996), Application of immunoaffinity column cleanup to aflatoxin Ml , J Food Protect, 59, 1011-1013. 

There has been considerable interest in the development and application of phyllosilicate clays (HSCAs) to selectively chemisorb aflatoxins in aqueous suspensions, including milk, reduce the uptake of aflatoxin by blood and its distribution to body organs such as the liver, reduce the transmission of aflatoxin Mi to milk in lactating animals and to decrease the toxic effect of aflatoxin to many animal species (Phillips et al., 1995). It is believed that the HSCAs when added to feeds act by the selective chemisorption of the aflatoxin in the gastrointestinal tract of the animal resulting in a marked reduction in the bioavailability of the aflatoxins. 

Table 11.9 Parameters and application of ammonia/aflatoxin decontamination procedures...

As sample extraction and sample handling are of general consideration for the more exotic biological matrices often found in food analysis, the application of IPCR in the research project MYCOPLEX [89], founded by the European Union, promises interesting new developments. This project is dedicated to the detection by IPCR of ochra- and aflatoxins in milk and coffee, focusing on sensitivity and simplified antigen extraction by dilution of the samples. 

T. Tanaki, A. Yoneda, Y. Sugiura, S. Inoue, M. Takino, A. Tanaka, A. Shinoda, H. Suzuki, H. Akiyama and M. Toyoda, An application of liquid chromatography and mass spectrometry for determination of aflatoxins, Mycotoxins, 52, 107-112 (2002). 

M. Walton, P. Egner, P.F. Scholl, J. Walker, T.W. Kensler and J.D. Groopman, Liquid chromatography electrospray-mass spectrometry of urinary aflatoxin biomarkers characterization and application to dosimetry and chemoprevention in rats, Chem. Res. Toxicol., 14, 919-926 (2001). 

Zhu JQ, Zhang LS, Hu X, Xiao Y, Chen JS, Xu YC, Fremy J, Chu FS Correlation of dietary aflatoxin B[ levels with excretion of aflatoxin M, in human urine. Cancer Res 1987 47 1848-1852. Groopman JD, Wogan GN, Roebuck BD, Kensler TW Molecular biomarkers for aflatoxins and their application to human cancer prevention. Cancer Res 1994 54 19078-191 IS. 

Actual and perceived food safety concerns have necessitated an increase in the monitoring of foods for such natural contaminants as aflatoxins and for residues of pesticides. Immunoassays can provide rapid, simple, and relatively inexpensive methods for the detection of analytes with specificity and with sensitivities directed at the levels of concern. Particularly for aflatoxins, they are rapidly assuming a significant role in the monitoring of foods. However, the misuse of these techniques can potentially compromise any food safety improvement that may result from increased surveillance. Experiences of the Division of Contaminants Chemistry in the development, validation, and applications of immunoassays for natural toxins is discussed. 

A third collaborative study (10) was conducted examining the Immuno Dot Screen Cup (Afla-20, IDS Cup), a test kit containing antibodies with considerable cross reactivity with aflatoxins B2 and G,. The manufacturer s procedure was also modified to increase the reliability of detection at 20 ng/g total aflatoxins, and to broaden the applicability to include peanut butter samples. 

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