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Gewählte Master / Diploma Thesis:

Johanna Brändle (2014): Die bakterielle Mikroflora von Vorarlberger Rohmilchhartkäse Eine Evaluierung potentieller Analysemethoden.
Master / Diploma Thesis - Institut für Lebensmittelwissenschaften, BOKU-Universität für Bodenkultur, pp 138. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
Due to its complex microbial composition and the changes within the microbial community during the production and ripening process, raw milk hard cheese is considered to have a unique and more intense flavor than other cheese products. However, some microorganisms of the natural cheese flora do not only contribute to the desired characteristic properties of the cheese, but may also cause quality defects in the final product, like bitterness, split formation, late blowing and irregular eye formation. The aim of this work was the evaluation of a suitable method for the analyzation of „Vorarlberger Bergkäse“, a special type of cheese with a protected designation of origin, that is produced by using traditional methods and a natural whey starter and whose microbial composition is not fully known yet. Therefore, by combining conventional cultural and modern molecular biological methods, information should be gained about the overall cheese microflora as well as certain groups of bacteria, which are suspected to cause quality defects in cheese. Particular attention was payed on the investigation of facultatively heterofermentative lactobacilli, propionic acid bacteria, enterococci and clostridia. For that purpose 13 cheese samples were analyzed by cultivation on different media, PCR-DGGE and following sequencing. The results showed high microbial counts for facultatively heterofermentative lactobacilli and propionic acid bacteria. In none of the samples clostridia were found. Enterococci were present in low numbers in some cheeses. Sequencing permitted a further classification of the isolates on the species level. The combination of cultural and molecular biological methods proved to be useful because some bacteria could only be detected by either one of the methods.

Beurteilende(r): Kneifel Wolfgang
1.Mitwirkender: Domig Konrad

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