Fera food safety experts are ideally suited to highlight and quantify a range of Nitrofurans within your food sample. Making use of extensive, industry accepted techniques our accurate results are invaluable when meeting regulations.

The nitrofurans are synthetic broad spectrum antimicrobial agents, which are prohibited from use in food animal production in the European Union due to concerns about the safety of their residues.. Metabolite residues covalently bind to proteins and as such  are detectable for several weeks after drug administration.  As a result these residues are a much better marker residue for the detection of abuse of nitrofurans.

Analytically, residues are checked only for marker metabolites of the 4 nitrofuran chemicals, in particular: 3-amino-2-oxazolidinone (AOZ) for furazolidone, 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ) for furaltadone, 1-aminohydantoin (AHD) for nitrofurantoin and semicarbazide (SEM) for nitrofurazone.

At Fera, samples shown to contain SEM residues are re-analysed employing this sample pre-treatment step. This is due to the fact that the presence of SEM can be attributable to sources other than the use of the nitrofuran drug nitrofurazone. Its presence in packaged food has been attributed in the past to the use of azodicarbonamide as a blowing agent used to foam the plastic gaskets in the metal lids of jars and bottles or as a flour treatment agent (dough improver). It is also present in the shells of crustaceans, after heat treatment. Any SEM derived from external sources will not be bound to the tissue and can be removed by sequential solvent washing of the tissue prior to nitrofuran analysis.

A minimum required performance limit (MRPL) for nitrofurans is set in the European Union for the metabolites of furazolidone, furaltadone, nitrofurantoin and nitrofurazone for poultry meat and aquaculture products at the level of 1 µg/kg for all metabolites (Commission Decision 2003/181/EC). In practice, these MRPL values are applied to other commodities including muscle, offal, milk and eggs.

Our industry experience means we understand the competitive environment you are working within, and we have made our testing activities as unobtrusive as possible, with a 10 working day turnaround and the need for only 200-250g per food sample.

Method

Feras innovative method results in Nitrofuran metabolites are extracted from tissue with dilute hydrochloric acid.  The metabolites are derivatised with 2-nitrobenzaldehyde, and the sample neutralised with alkaline buffer. The resulting extract, containing 2-nitrobenzaldehyde derivatives of nitrofuran metabolites, is applied to a solid phase extraction (SPE) cartridge to remove compounds which could interfere with the analysis.  Any residues present are analysed using liquid chromatography–tandem mass spectrometry (LC–MS/MS), with negative ion electrospray.