Differentiation of Penicillium commune and Penicillium palitans isolates from cheese and indoor environments of cheese factories using M13 fingerprinting Original Research Article

Penicillium commune and Penicillium palitans isolates previously isolated from cheese samples and the indoor environment in four cheese factories were investigated using Polymerase Chain Reaction (PCR) fingerprinting with the core sequence of the phage M13 as primer. In total, 55 isolates of P. commune and 49 isolates of P. palitans were investigated. Four and seven different M13 fingerprinting profiles were found among the P. commune andP. palitans isolates, respectively. Three fingerprinting profiles dominated for each species, comprising 98% and 86% of the P. commune and P. palitans isolates, respectively. Each of the dominating profiles was found in at least three factories and was thus not factory-specific. For each species, one of the fingerprinting profiles was found only once. In addition, one profile of P. palitans was found twice and in one factory only. The M13 fingerprinting grouped theP. commune and P. palitans isolates and gave useful information with respect to identifying whether isolates of the same species could originate from the same contaminating strain.