mutagenicity of commercial monascus fermentation products and the role of citrinin contamination pigments produced as secondary metabolites by various isolates of moulds belonging to the genus monascus have been used traditionally as colorants in oriental food modern food industry has rediscovered these moulds as promising source for natural colorants however recent studies evidence that one of the secondary metabolites produced by monascus is identical in structure to the mycotoxin citrinin thus a sensitive hplc method was developed to analyse these food colorants for contamination with citrinin the mycotoxin could be detected in all the commercial monascus samples at concentrations varying between 02 to 171 microgg in addition the mutagenicity of commercial monascus samples applying salmonellamicrosome assay and salmonellahepatocyteassay was investigated and compared to the results obtained with citrinin citrinin and two monascus extracts induced a positive dose depending mutagenic response in the salmonellahepatocyteassay applying strain ta98 however no mutagenicity could be detected in the salmonellamicrosome assay neither with nor without s9mix for citrinin and monascus extracts applying ta98 ta100 ta1535 ta1538 and ta97 these findings provide further evidence that citrinin requires complex cellular biotransformation to exert mutagenicity