The occurrence of yeasts in dairy products is significant because they can cause spoilage, effect desirable biochemical changes and
they may adversely affect public health. While fermentative and spoilage activities of yeasts at elevated temperatures are well known
in many food and beverage commodities, little attention has been given to the specific occurrence and significance of yeasts in dairy
products at these temperatures. Since yeasts play a substantial role in the spoilage of commercial fruit yoghurts, especially when
cold storage practices are neglected, the deterioration of yoghurt samples obtained from the manufacturers were evaluated at different
temperatures for a period of 30 days during this study. Total yeast were enumerated, isolated and identified from the yoghurt
samples. The highest number of yeast populations, up to 105 and 106 cfu/g, was found when yoghurts were exposed to elevated
temperatures in the range of 25 C, while lower yeast counts (103 and 104 cfu/g) were obtained from samples kept refrigerated at a
temperature of 5 C. Based on the results obtained, the interaction between the yeasts and lactic acid bacteria resulted in a decline in
pH values and the stabilization of viable lactic acid bacterial loads. The most prevalent yeast species isolated, included strains of
Kluyveromyces marxianus, Saccharomyces cerevisiae, Saccharomyces exiguus andYarrowia lipolytica.