News item [01-2005]:
March 21, 2005
New techniques for pesticide residues [01-2005].
The European Union through the European Food Safety Authority (EFSA) is one of the strictest regulatory agencies in the world governing the production and distribution of consumable agricultural products.
The Australian agricultural community whether a typical farm producing goods for export or other food commodity producers are being increasingly asked to determine through testing that their goods can meet the international and European standards for residues of insecticides, fungicides and herbicides. In 1992 the EU embarked on a total review of all plant protection products that is to be completed in 2008. Manufacturers and exporters hoping to send product to the EU will have to “defend” the safety level of the use of any chemical that has been used to produce the product. Already a large number of older chemicals have been or are being phased out and withdrawn for reasons of toxicity efficacy or environmental impact.
Typically, when a compound is de listed its maximum permitted residue level ( MRL) in food reverts to the limit of Detection ( LOD) which in Europe is set at 0.01 mg/ Kg ( 10 ppb). It is proposed that the new MRL legislation will set a common LOD of 0.01 mg/Kg for any commodity/pesticide combination for which a higher level cannot be justified. The aim ultimately is to set levels which will standardise the MRLs around the globe. At the moment however MRLs are often country specific for example the level of a pesticide may be ten fold higher or lower depending on the country imposed MRL. What is needed for testing is the requirement for reliable, sensitive and comprehensive analysis of pesticide residues in food to ensure consumers that all their fruits and vegetables are healthy.
Traditionally in the laboratory pesticide residues in foods have been monitored with multi residue methods such as gas chromatography coupled with selective detectors or mass spectrometry. There is however an ever increasing list of newer substances that, while safer, have proved difficult to detect and monitor because they are not amenable to GC or not detectable at sufficiently low levels to asses the compliance with the MRL required. This means the laboratory has to adapt its technology to be able to test for the new residues. The laboratory needs to also detect to lower and lower levels. The challenge is to also ensure that what you have detected is genuinely a pesticide and not a co extracted artefact.
The common technique of GC coupled to MS has now been improved still further to use a new detection solution and that is to use a triple quadrupole MS system made by Varian Inc in Walnut Creek, California. This new technique has been now recently been implemented by Advanced Analytical by purchasing this instrument to minimise the potential interference from co- extractants. We believe we are the first laboratory in Australia to do so and unique in being able to now offer an increased level of surety in the detection and identification of these newer pesticides and to lower levels. Advanced analytical has a triple quadrapole system on its Liquid chromatography system ( LCMSMS) and now also for its GCMS to make it a GCMSMS. This will allow a validated technique for an increasing range of diverse pesticide classes that can be detected by either or both techniques. Pesticides classes like carbamates, macrocylic lactones, morpholines and benzimidazoles that were traditionally difficult to analyse, can now be detected on a single extract. This will be of particular importance to those in Australia who must continue to assure our imports and our exports are compliant with the newer, lower pesticide residue levels.
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