Differentiation of Penicillium roqueforti from Closely Related Species Contaminating Cheeses and Dairy Environment

Currently, Penicillium roqueforti and the closely related P. carneum and P. paneum are identified based on their macromorphology, micromorphology, and molecular properties, the determination of which involves time-consuming procedures. Culture collections focused on dairy isolates of P. roqueforti require quick and efficient tools for routine applications to identify the (a) taxonomy affiliation and (b) morphological properties of strains that influence the sensory properties of blue-veined cheeses. Here, we assessed the morphological variability of P. roqueforti, P. carneum, P. paneum, and P.crustosum on artificial, Edam-like, and Roquefort-like media. Molecular tools were used to test P. roqueforti strains and clones effectively. A novel primer, PrsF, was tested for specificity within strains and isolates of P. roqueforti compared to P. carneum, P. paneum, and P. crustosum. The results reveal that PrsF was specific to the P. roqueforti samples and did not amplify the other tested Penicillium species. Identification based simultaneously on the specificity of the PrsF primer pair and cultivation of P. roqueforti strains on Roquefort-like medium represents an effective method for expanding the collections and practical use of P. roqueforti in the dairy industry.