Molecular Identification and Enzymatic Characterization of Fungi Isolated During Beef Aging

Dry-aged beef is valued for its distinctive flavor and tenderness, but the fungal communities associated with the product and its aging environments remain insufficiently characterized. This study characterized the culturable fungal community of dry- and wet-aged beef from Albera and Bruna dels Pirineus cattle, as well as the aging chambers where the beef was produced, and assessed the proteolytic and lipolytic potential of the isolated fungi. Meat samples and chamber air were analyzed using culturomics and ITS sequencing. Among 291 fungal isolates, yeasts predominated in meat samples, with Candida, Yarrowia, and Debaryomyces as the main genera, whereas molds were more frequent in chamber samples, especially Penicillium and Cladosporium. Dry-aged meat exhibited a higher diversity of fungal genera and species than wet-aged meat, and some taxa detected in meat were also present in the corresponding aging environments, suggesting a possible environmental contribution. Enzymatic assays showed that many molds and yeasts displayed proteolytic and lipolytic activity, with Yarrowia spp. and Penicillium spp. showing notable activity. However, these assays were performed in vitro and should be interpreted as indicating enzymatic potential rather than direct activity in meat. Although potentially mycotoxigenic genera such as Aspergillus, Cladosporium, and Penicillium were detected, no mycotoxin analyses were performed. Accordingly, no conclusions can be drawn regarding toxin production, but their presence underscores the need for careful control of aging conditions. Overall, the study expands the current knowledge of culturable fungi associated with beef aging systems and provides a basis for future work on the technological and safety relevance of the identified isolates.