Københavns Universitet

Multiple industries


Bioprotective abilities of brine yeasts on cheese models at Københavns Universitet

Brining of cheeses is an important step during manufacturing, influencing cheese structure and flavour as well as having a high impact on the microbial growth. Salting of most semi-hard cheeses is performed by immersion into brines with about 21% NaCl (w/w) at 10–14 °C. Cheese brines are rarely renewed but pH is adjusted to 5.2-5.3 and salt is added regularly to replenish the salt, which has diffused into the cheeses. As cheese brines are often used in the production of several batches they become a natural source of microorganisms. During this project, complex microbiotas from Danish cheese brines were identified and isolated. Functionalities related to flavor development and bioprotective abilities of selected brine yeasts were studied.

The aim of this Master thesis project is to study the ability of the brine selected cultures to establish on the cheese surface and to study bioprotective abilities of selected brine cultures against dairy spoilage molds on cheese surfaces. This involves brining pf cheeses mimicking production conditions, for inoculation of cheese surfaces with selected brine cultures. Establishment of microorganisms on cheese surfaces is studied by quantification using culture and non-culture techniques. Bioprotective abilities of selected brine cultures will be evaluated using image analyses.

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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