[Determination and occurrence of zearalenone in cereals and mixed feeds]

An HPLC method with fluorescence detection is described for the determination of zearalenone in cereals and mixed feeds. Samples are extracted with chloroform at low pH and cleaned up using an acid-base treatment or gel-permeation chromatography (GPC). Mixed feeds must additionally be cleaned up with extraction columns, because of their different compositions. With the extraction procedure described and GPC clean-up, ochratoxin A can be determined simultaneously. The limit of determination for zearalenone is 2.5 micrograms/kg. The average recovery rate, tested in the range 3.5 to 85 micrograms/kg was found to be 97%. Using this method, 91 samples of cereals and mixed feeds, harvested in 1989, were examined. The contamination rate was 42%. The results are discussed.