Københavns Universitet

Multiple industries


Microbial interactions between brine yeast and molds on cheese model surfaces at Københavns Universitet

Mold contamination can appear throughout the entire cheese production, and especially during the ripening period, mold contamination is observed. This result in reduced cheese quality including visible and invisible defects such as colony formation on the cheese surface and potential formation of unwanted secondary metabolites. Biocontrol by use of indigenous Debaryomyces hansenii strains is a promising approach for preventing the germination and growth of contaminating molds in the dairy industry. In the project, antagonistic activities of D. hansenii strains, isolated from cheese brines from different Danish dairies were established in vitro. However, knowledge on the microbial interactions and bioprotective abilities of selected brine yeasts on cheese surfaces still needs to be investigated.

The aim of this Master thesis project is to study microbial interactions between selected brine yeasts and contaminating dairy molds on cheese surfaces. This involves brining of cheeses mimicking production conditions, for inoculation of cheese surfaces with selected brine cultures. Quantifications of microorganisms will be performed to study population dynamics using culture and non-culture techniques. Spot-tests is used to evaluate bioprotective abilities of brine selected yeasts and microbial interactions between yeasts and molds.

Master thesis (30 or 45 ECTS)

Supervisors: Lene Jespersen (lj@food.ku.dk) and Pernille Greve Johansen (pernillejohansen@food.ku.dk)

Section: Food Microbiology and Fermentation

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