YEAST DIVERSITY IN BLUE MOULD RIPENED CHEESES.
ABSTRACT
During the ripening process of blue veined cheese, different microbial groups interact
and contribute to the final product. One of the most important of these groups are yeast.
Further studies are needed to clarify their specific contribution to the ripening process.
In order to accomplish this, a suitable and satisfactory enumeration medium is needed.
Consequently, ten selective media were evaluated for their potential to inhibit and
suppress the growth of moulds and bacteria without affecting the yeasts. Based on
statistically compared data, no significant difference could be found amongst the ten
media, except for one. Further studies were performed on the three media considered
to be the most effective, MEA + Ox, MEA + NaCl and MEA + BP based on qualitative
results. Accordingly, the three selected media were evaluated based on their ability to
support the growth of the five most frequently occurring yeast species in blue veined
cheese. No significant difference was obtained between two of the three media. MEA +
NaCl however, was unable to support the growth of two of the five most dominant yeast
species. MEA + Ox and MEA + BP proved to be superior for the enumeration and
isolation of yeasts from blue veined cheese. DRBC, RBC and DG18 proved satisfactory
regarding the enumeration of yeasts, whereas OGGY, MEA + SP and molybdate
containing media are not recommended.
Key words: Selective media, Yeasts, Moulds, Enumeration
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-03172004-153159 |
| Date | 23 March 2004 |
| Creators | Human, De Jager Paul |
| Contributors | Professor B.J. Viljoen |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://lourie.uovs.ac.za//theses/available/etd-03172004-153159/restricted/ |
| Rights | mixed, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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