Humans have been using milk from cattle for at least 10 000 years. During millennia, techniques for the refinery of milk to cheese have evolved resulting in the transition from small scale local production to the industrialized manufacture seen today. A problem faced today is the occurrence of dairy spoilage yeasts, of whom species belonging to the genus Candida is most prevalent. Methods to combat spoilage fungi involves the use of chemical preservatives, of which salts of sorbic acid are widely used. In water, the sorbate ion accepts a proton from the oxonium ion resulting in the formation of sorbic acid. Sorbic acid can diffuse into and over cellular membranes of yeasts, where it disrupts a range of functions. The most important being the disruption of proteins located in the mitochondrial membranes, resulting in an inhibition of the respiratory chain. The process of salting cheese is usually done by submersion in brine. The brine used is home to a diverse microflora, sometimes comprising said yeasts. The purpose of this work was to develop a method to investigate whether a reduced use of potassium sorbate in brine is possible. Two methods were developed, one where yeast was inoculated into different concentrations of potassium sorbate. The other used yeast in suspension derived from a simulated brining tank. The results showed that the simulated brining tank worked better, and a potential reduction to 1/3 of the current use of sorbate is possible. However, the experimental basis for this conclusion, even though supported by previous studies, is weak.

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L’objectif de cette étude exploratoire était de mieux comprendre, du point de vue des animateurs/animatrices qui oeuvrent auprès des jeunes, le phénomène de l’engagement des jeunes dans les programmes parascolaires. Des entretiens qualitatifs ont été entrepris à cette fin avec six animateur(trices). Plusieurs obstacles à l’engagement ont été identifiés, la plupart étant extérieurs aux jeunes. Quelques actions et attitudes spécifiques des animateur(trices) ont été relevées comme importantes pour aider les jeunes à surmonter ces obstacles. De plus, la structure et le contenu du programme, ainsi que l’environnement de groupe, jouent des rôles primordiaux. Les dimensions soulevées par les animateur(trices) ont permis d’enrichir et rendre plus holistique un modèle d’engagement qui a été développé à partir d’une recension des écrits dans ce domaine. Finalement, les implications pour la formation des animateurs(trices) et pour la structure des programmes pour les jeunes ont été explorées. / The objective of this exploratory study was to better understand young people’s engagement in out-of-school-time youth development programs from the perspective of frontline youth workers. Qualitative interviews were carried out with six youth workers to this end. A number of obstacles to engagement were identified, the majority of which are external to youth. Positive dispositions towards youth by youth workers were found to be key in overcoming some of these obstacles, although program content and structure, as well as group climate also play an important role. The key dimensions of engagement the interviewees raised led to an elaboration of a current model of engagement found in the literature, making it more holistic. Implications for the training of youth workers and the structure of youth programs are discussed.

Im Rahmen einer Reanalyse von vier Erhebungen an jugendlichen und erwachsenen Probanden in den neuen und alten Bundesländern in den Jahren 1990 bis 1991/92 wurden Angaben zu Indikatoren für Depressivität, Angst/psychosomatische Beschwerden und Substanzgebrauch in Ost- und Westdeutschland verglichen. Zum Zeitpunkt der Untersuchungen gab es im Gegensatz zu der von einzelnen Autoren angeführten Erwartung keine eindeutigen Hinweise auf eine insgesamt erhöhte psychiatrische Morbidität in den neuen Bundesländern. Depressive Symptome und der Gebrauch von illegalen Drogen und Medikamenten sind durchgängig in den alten Bundesländern häufíger nachzuweisen als in den neuen Bundesländern. Allenfalls ergaben sich für die Stichproben Ost für einzelne depressionstypische sowie einzelne psychovegetative Symptome und für Alkoholgebrauch statistisch signifikant erhöhte Werte. Da keine Diagnosekriterien erhoben wurden, muβ die Aussagekraft der Daten dahingehend eingeschränkt werden, daβ lediglich Indikatoren für psychische Auffälligkeiten erhoben wurden.

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Univ., Diss.--Potsdam, 2004. / Literaturverz. S. 371 - 400.

Univ., Diss.--Tübingen, 2004. / Literaturverz. S. 154 - 175.

Thesis (doctoral)--Universität Osnabrück, 2008. / Includes bibliographical references (p. [417]-439) and glossary.

Revision of thesis (Ph. D.)--University of Manchester, 1997. / Includes bibliographical references (p. [255]-272) and index.