Simultaneous determination of ochratoxin A, mycophenolic acid and fumonisin B(2) in meat products.
Here we present a method for simultaneous determination of the fungal metabolites mycophenolic acid, ochratoxin A (OTA) and fumonisin B(2) (FB(2)) in meat products. Extraction was performed with water-acetonitrile, followed by acetone-induced precipitation of salts and proteins. Purification and identification of analytes was performed by mixed-mode reversed-phase anion-exchange chromatography in direct ion-exchange mode, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) detection. Quantification was based on isotope dilution with fully (13)C-labelled FB(2) and OTA, and matrix-spiked calibration curves. Fermented sausages inoculated with an OTA- and FB(2)-producing strain of Aspergillus niger were analysed, but no analytes were detected. Analysis of 22 retail products showed one Parma meat with a very high level of OTA contamination (56-158 microg/kg) that clearly exceeded the Italian regulatory limit of 1 microg/kg. This sample and uninfected control samples were subsequently reanalysed, and the high OTA content was verified by two other techniques: (i) LC-time-of-flight MS confirmed the accurate mass as well as chlorine isotope pattern; and (ii) sample methylation in methanol-BF(3) and subsequent LC-MS/MS provided indirect confirmation by detection of the OTA methyl ester. In the contaminated Parma ham, the high OTA level most likely originated from growth of Penicillium nordicum on the meat.
Sørensen
Louise Marie
LM
Department of Systems Biology, Technical University of Denmark, Building 221, 2800, Lyngby, Denmark.
Mogensen
Jesper
J
Nielsen
Kristian Fog
KF
D002138:Calibration; D002853:Chromatography, Liquid; D037341:Fumonisins / Q000032:analysis*; D008461:Meat Products / Q000032:analysis*; D009173:Mycophenolic Acid / Q000032:analysis*; D009793:Ochratoxins / Q000032:analysis*; D053719:Tandem Mass Spectrometry
D037341:Fumonisins; D009793:Ochratoxins; C056934:fumonisin B2; C025589:ochratoxin A; D009173:Mycophenolic Acid