The Monitoring of Triphenylmethane Dyes in Aquaculture Products Through the European Union Network of Official Control Laboratories

Abstract

Aquaculture has been the fastest growing animal production industry for the past four decades, and almost half of the fish eaten in the world are now farmed fish. To prevent diseases in this more intensive aquaculture farming, use of therapeutic chemicals has become a basic choice. The monitoring of malachite green, a triphenylmethane dye and one of the oldest and widely used chemicals in fish production, has gained more interest since the mid 1990s when this substance was finally proven to be toxic enough to be prohibited in seafood products destined for human consumption. The enforcement of the European Union (EU) regulation of this banned substance along with some other triphenylmethane dye congeners and their metabolites in its domestic production and in seafood imports was undertaken through the National Residue Monitoring Plans implemented in nearly all of the 28 EU member states. The reliability of the overall European monitoring of this dye contamination in aquaculture products was assessed by using the results of proficiency testing (PT) studies provided by the EU Reference Laboratory (EU-RL) in charge of the network of the EU National Reference Laboratories (NRLs). The proficiency of each NRL providing analytical support services for regulating dye residues was carefully checked during three PT rounds. In the process, the analytical methods developed and validated for this purpose have gradually been improved and extended over the last two decades.

Malachite green in food

“…The EURL, Anses-Foug eres (France), provides proficiency testing for National Reference Laboratories in charge of control for dye residues in aquaculture products with three rounds having been organised covering trout (2005,2009) and prawn (2013) samples (Verdon et al, 2015). The EURL, Anses-Foug eres (France), provides proficiency testing for National Reference Laboratories in charge of control for dye residues in aquaculture products with three rounds having been organised covering trout (2005,2009) and prawn (2013) samples (Verdon et al, 2015).…”

“…Several proficiency tests and interlaboratory studies have been reported for MG/LMG in fish. The EURL, Anses-Foug eres (France), provides proficiency testing for National Reference Laboratories in charge of control for dye residues in aquaculture products with three rounds having been organised covering trout (2005,2009) and prawn (2013) samples (Verdon et al, 2015). In January 2008, the Proficiency Test Advisory Board, Government Laboratory, Hong Kong reported on a proficiency test (APLAC T058) aimed at evaluating the testing capability of 48 participating laboratories in the quantitative analysis of MG and LMG in swamp eels; 48% and 62% of participants had satisfactory results (z-score ≤ 2) for the determination of MG (assigned value 28.2 lg/kg) and LMG (assigned value 2.21 lg/kg), respectively (Wong, 2008).…”

“…However, MG/LMG residues in aquaculture products have been detected in monitoring programmes in EU Member States (Verdon et al, 2015), indicating its continued use in certain geographic areas and the need for continued surveillance of fish products. However, MG/LMG residues in aquaculture products have been detected in monitoring programmes in EU Member States (Verdon et al, 2015), indicating its continued use in certain geographic areas and the need for continued surveillance of fish products.…”

“…MG is not registered for use in food-producing animals in the EU (see Section 1.3.5). However, MG/LMG residues in aquaculture products have been detected in monitoring programmes in EU Member States (Verdon et al, 2015), indicating its continued use in certain geographic areas and the need for continued surveillance of fish products. Use of MG has not been reported in bivalve culture, only in fish and crustacean farming.…”

Certain Dyes as Pharmacologically Active Substances in Fish Farming and Other Aquaculture Products

“…For regulatory analysis, the method performance for MG, LMG, CV, LCV, and BG was characterized by decision limit and detectability (CCα and CCβ) at and below 0.5 μg/kg, trueness ranging from 100% to 110% recovery, and precision of 10% RSD. Alternative instrument parameters were additionally described for the identification of the LBG analyte in incurred trout by UHPLC-LTQ-Orbitrap TM -MS. 31 The method was included in several proficiency testing studies conducted by the EU Reference Laboratory for EU Member States 162 and was the method suggested in a recent Food Emergency Response Network proficiency test conducted by the USFDA for state and federal laboratories in the USA. In 2012, the method was established as AOAC First Action Method 2012.25 for future consideration as an AOAC Official Methods of Analysis.…”