AimsTo provide an efficient technique for monitoring the off-flavoured fungal compound geosmin. Methods and ResultsGeosmin-associated gpe1 gene of Penicillium expansum displayed 99% similarity to cytochrome P450 gene of geosmin-producing P.restrictum, but 40% similarities to geosmin biosynthesis, non-cytochromic gene of Streptomyces avermitilis and cytochrome P450 genes of non-geosmin-producing Neotyphodium lolii, Phoma betae and P.paxilli. Serial 10-fold dilutions of P.expansum's DNA was subjected to a previously reported qPCR assay (Atoui etal. 2007), utilizing gpe1 specific primer pair SNgpe1F/SNgpe1R'. A linear relationship between DNA quantity and Cycle Threshold (C-t), with strong correlative coefficient, was observed. Using the available physico-chemical method, geosmin was quantified in 188 grape samples. Penicillium spp's DNA was quantified in these samples, utilizing the developed qPCR assay. A strong positive correlation (R-2=097) between Penicillium's DNA and geosmin concentration was observed. Furthermore, <50ngl(-1)Penicillium's DNA corresponds to geosmin level below the permitted intensity limit i.e. 4, for Flavour Profile Analysis'. ConclusionsPenicillium spp., genomic DNA level can provide an efficient way to quantify geosmin. Significance and Impact of the StudyThis particular qPCR technique can be utilized in numerous food industries, for the timely detection and monitoring of geosmin contamination.