The total solution for the screening for malachite green and crystal violet

With the launch of the EuroProxima Malachite Green Total ELISA, R-Biopharm offers a screening test that is fully validated for the measurement of malachite green, leucomalachite green, crystal violet and leucocrystal violet in fish and shrimp.

Triphenylemethane dyes such as malachite green (MG) and crystal violet (CV) are a group of organic dyes widely used in industry for dying purposes. They have been also used in aquacultures to treat and prevent fungal and parasitic infections in fish, however due to their toxic effects they are not authorised to be used in fish for human consumption. These dyes are metabolised in fish to the reduced leuco forms: leucomalachite green (LMG) and leucocrystal violet (LCV) that can persist in tissues for a long time. The detection of the residue of these dyes in aquaculture products indicate illegal use as only zero levels are accepted.

In the European Union the minimum required performance limit for a method for the detection of a sum of malachite green and leucomalachite green is 2 µg/kg (Commission Decision 2002/657/EC). In accordance with Commission Decision 2002/994/EC any imports of aquaculture fishery products from China should be tested for the presence of malachite green, crystal violet and their metabolites.

To provide a new method for simultaneous detection of residues of both malachite green and crystal violet, EuroProxima developed Malachite Green Total (MGT) ELISA. The test is applicable for analysis of fish and shrimp samples. During the sample preparation procedure, malachite green, crystal violet, leucomalachite green and leucocrystal violet are first extracted from the homogenised samples. Then leucomalachite green and leucocrystal violet are converted to their parent compounds in a fast oxidation step. Samples are finally analysed by MGT ELISA and results are expressed as total MG concentration: a sum of malachite green, crystal violet, leucomalachite green and leucocrystal violet.

This ELISA is validated wit a limit of detection, a detection capability and a cross-reactivity in seven types of fish and shrimp. With a detection capability of 0.3 µg/kg the requirement of the European performance limit is very well reached. The test offers a fast and simple sample preparation; an incubation for the required oxidation step is not necessary.