Detection of the nephrotoxic mycotoxin citrinin in foods and food colorants derived from Monascus spp

A method for the detection of citrinin in food was developed by using high- affinity monoclonal antibodies against this mycotoxin. Samples were acidifi ed 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 p urified by immunoaffinity chromatography (IAC). The detection limit for cit rinin in food was 2 mu g/kg. This method was applied to analyse 12 vegetari an "meat-like" products and 11 Asian food purchased in retail stores in Bav aria. Using the EIA citrinin could be detected in eight vegetarian "meat-li ke" products and two Asian food in a concentration range of 22-105 mu g/kg. Ail but one positive results could be confirmed by HPLC analysis. All posi tive findings could be attributed to the use of rice fermented by Monascus spp. for food colouring. Furthermore, citrinin concentrations of 2800 mu g/ kg and 157 mu g/kg were detected by HPLC analysis in two samples designated as natural food colorants. In four samples of red-mold rice from Japan, ci trinin was found in lower concentrations (42-86 mu g/kg).