Characterization of Tiroler Bergkäse PDO cheese: A multimethodological approach

Tiroler Bergkäse PDO is a traditional Austrian hard cheese from Tyrol, a product of great regional significance. This study aimed to describe Tiroler Bergkäse PDO by comparing it with Bergkäse without PDO from Tyrol and a Stilfser type cheese from South Tyrol. To account for variability, three cheese wheels from three production days were analyzed for each cheese. Multimethodological characterization included quantitative Polymerase Chain Reaction, Ion Exchange Chromatography, and Headspace-Solid Phase Microextraction/Gas Chromatography-Mass Spectrometry. The characterization Tiroler Bergkäse PDO should impart potentially unique features. Multivariate analysis of the bacterial composition, free amino acid content, and volatile fraction revealed differences between all cheeses (α = 0.05). A triangle test confirmed significant differences, with more pronounced differences between the Bergkäse type cheeses and the Stilfser type cheese. The Stilfser type showed distinct differences in bacterial composition, amino acid content, and volatile profile, making it less similar to the Bergkäse type cheeses. Multivariate analysis also revealed differences between the PDO and non-PDO Bergkäse which is characterized by high levels of L. delbrueckii due to its starter culture, and a high free amino acid content from longer ripening, alongside elevated levels of hexanal and acetoin. In contrast, Bergkäse without PDO shows high levels of 2,3-butanediol and 2-nonanone, alongside high levels of L. mesenteroides, L. lactis subsp. lactis, and L. lactis subsp. cremoris. It was possible to distinguish between Tiroler Bergkäse PDO from non-PDO cheeses by microbial, amino acid, and volatile profiles and support the use of advanced methods to characterize regional foods.