Immunochemical Methods General Aspects

Within the past decade numerous reports have been published concerning the use of immunoassays (IAs) for mycotoxin analysis. IAs are rapid, simple, specific, sensitive, and portable and require little analyst training or skill

(129). Because IAs are extremely sensitive, often in the picogram/milliliter range, simple dilution of the sample can often remove the need for extensive sample cleanup. However, with most food matrices, some form of extraction of the sample is needed. Three IAs that have been developed for mycotoxin analysis include the radioimmunoassay (RIA), the enzyme-linked immunosorbent assay (ELISA), and the IAC assay. The RIA and ELISA analyses are based on the competition of binding between unlabeled mycotoxin in the sample and labeled mycotoxin in the assay for the specific binding sites of antibody molecules

(130). The IAC assay involves the use of antibody columns that specifically trap the mycotoxins in a sample. Trapped mycotoxin can then be eluted and quantified. Some IAs require specialized equipment, such as ELISA readers, tube readers, scanners, or fluorometers for quantitation, while others rely on visual quantitation (129).

Chu (131) listed four main criteria that need to be considered when choosing an IA for mycotoxin analysis. First, a well-labeled mycotoxin (as a marker) is needed in the assay system in addition to a specific antibody. Second, a good method for the separation of free and bound forms of mycotoxin is needed. Third, the degree of specificity of the antibody in the assay should be known. Finally, the sample matrix should be tested before the assay to determine if structurally related compounds in the sample react with the antibody.

Various commercial kits using immunochemical techniques such as ELISA and IAC assays are now available for several mycotoxins including aflatoxins, deoxyniva-lenol, fumonisins, ochratoxin A, and zearalenone (129). Such commercial tests will find universal acceptance if officially listed to be at least comparable with present analytical methods. Such assessment is currently under way with the AOAC International in the United States and the Ministry of Agricultural, Food and Fisheries (MAFF) in the United Kingdom (132). Several quantitative IA methods have been adopted as AOAC International Official methods for mycotoxins (10,129,130,133).

The development of recombinant antibodies and the making of reusable IAC should reduce the cost of IA and make it one of the more important techniques in the analysis of mycotoxins. In addition, recently published methods

(134.135) have indicated that the possibility exists for quantifying several mycotoxins in the same IA. Several excellent reviews have been written on IA in general

(132.136) and on the use of IA in the analysis of mycotoxins (56,58,129,137-140).

Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

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