Metabolites of Monascus ruber in silages

A total of 233 silages were examined and found that Monascus ruber was present in 43 samples with counts between 1 x 10(3) and 9 x 10(6) colony-forming units (CFU)/g (mean: 2 x 10(5) CFU/g). Monacolin K-L and the hydroxy acid monacolin K-A were detected by liquid chromatography-mass spectrometry in 45 and 50 of 233 samples at levels ranging from 25-15 600 and 28-65 400 mug/kg, respectively. Citrinin was found with highperformance liquid chromatography-fluorescence detection (FLD) in 14 (6%) samples, the concentrations varied between 2.4 and 64.2 mug/kg. The concentrations of citrinin were low and toxic effects are not anticipated. Monacolin K-A and monacolin K-L occur frequently and in considerable amounts in silages. These metabolites are believed to influence the metabolic activity of rumen anaerobic fungi resulting in a poorer digestion of crude fibre.