Aims The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage mouldsPenicillium expansumandPenicillium nordicum. Methods and Results Conidial germination of the testedPenicilliumspp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4 center dot 4-16 center dot 7% at 7 center dot 5 mmol l(-1)and completely inhibited at 15 mmol l(-1)2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63 center dot 5 - 75 center dot 7% membrane damage upon treatment with 15 mmol l(-1)2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth ofP. expansumandP. nordicumwas additionally confirmed. Conclusions 2-phenylethanol inhibits conidial germination and growth ofP. expansumandP. nordicumin a nonlethal, reversible and concentration-dependent manner. Significance and Impact of the Study The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.