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J Food Prot. 2008 Mar;71(3):590-4.

Detection of melamine using commercial enzyme-linked immunosorbent assay technology.

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Division of Bioanalytical Chemistry, Office of Regulatory Science, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, Maryland 20740, USA.


Recent cases of adulteration with melamine have led to the need for rapid and reliable screening methods. To meet this need, commercial enzyme-linked immunosorbent assay (ELISA) test kits for the detection of triazines were evaluated. The recently released Melamine Plate kit (Abraxis, Warminster, Pa.) displayed a limit of detection of 9 ng/ml for melamine in phosphate-buffered saline (PBS) and approximately 1 microg/ml for melamine added to dog food. An atrazine ELISA test kit produced by Abraxis required 0.2 mg/ml to generate a response more than four times the standard deviation from background. In contrast, with the EnviroGard Triazine Plate kit (Strategic Diagnostics, Inc., Newark, Del.), 1.5 mg/ml melamine in PBS generated a signal only one standard deviation from background, which was insufficient to define a limit of detection. Extraction based on dilution with 105 mM sodium phosphate/75 mM NaCl/2.5% nonfat milk/0.05% Tween 20 (UD) enabled detection of fivefold less melamine in dog food than did use of the procedure recommended by the manufacturer, which entailed extraction into 60% methanol, sonication, centrifugation, filtration, and further dilution into 10% methanol/PBS. Using the Abraxis Melamine ELISA, both extraction protocols yielded identical results with a dog food sample adulterated with melamine. The recovery of melamine spiked into gravy from dog food using UD was 74% +/- 4%. In conclusion, the recently released Abraxis ELISA for melamine proved to be a useful alternative to more cumbersome methods.

[Indexed for MEDLINE]

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