Evaluating starter culture potential of wild Penicillium roqueforti strains from moldy cheeses of artisanal origin

Abstract

Penicillium roqueforti from native food habitats can provide more insights into moldy cheese production. The objective of this study was to evaluate the starter culture potential of wild P. roqueforti strains from moldy cheese samples of artisanal origin. Their starter culture potential was studied after culturing, morphological analysis, and PCR-identification of P. roqueforti isolates. Overall, 17 of 623 cultured fungal strains were identified as P. roqueforti by PCR. The identified strains showed high proteolytic activity (8.9 ± 8.4), followed by amylolytic (0.413 ± 0.289) and lipolytic (0.29 ± 0.28) activities, with an optimum acid pH of 6.0. In addition, the strains were inhibitory on Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and S. typhimurium, susceptible to TE, CPD, and CTX whereas resistant to CAZ, CN, K, VA, and C, and antagonistically suppressed by some lactic acid bacteria species. The mean highest viability was detected as 7.4 ± 1.2 g/CFU in a medium of sucrose, peptone, KH2PO4, MgSO4⋅7H2O, KCI, whey, and milk powder under batch-fermentation conditions of at 25 ◦C for 72–96 h, with pH 6.0 and 10% dissolved oxygen. In summary, our results showed that wild P. roqueforti isolates could meet specific requirements for becoming fungal starter cultures for moldy cheese production.