Nachweis des nephrotoxischen Mykotoxins Citrinin in Lebensmitteln und mit Monascus spp. hergestellten Lebensmittelfarbstoffen

A method for the detection of citrinin in food was developed by using high-affinity monoclonal antibodies against this mycotoxin. Samples were acidified and extracted with dichloromethane. The extracts were purified by liquid-liquid-partitioning with bicarbonate and analyzed by an enzyme immunoassay (EIA). Positive results obtained by this screening assay were confirmed by HPLC and fluorescence detection. For this purpose, extracts were further purified by immunoaffinity chromatography (IAC). The detection limit for citrinin in food was 2 μg/kg. This method was applied to analyse 12 vegetarian meat-like products and 11 Asian food purchased in retail stores in Bavaria. Using the EIA citrinin could be detected in eight vegetarian meat-like products and two Asian food in a concentration range of 22-105 μg/kg. All but one positive results could be confirmed by HPLC analysis. All positive findings could be attributed to the use of rice fermented by Monascus spp. for food colouring. Furthermore, citrinin concentrations of 2800 μg/kg and 157 μg/kg were detected by HPLC analysis in two samples designated as natural food colorants. In four samples of red-mold rice from Japan, citrinin was found in lower concentrations (42-86 μk/kg).