摘要：In the present study, the commercial biopreservative culture “Bio Profit” was tested against yeast or mould growth in set-type yoghurt. Strains of Kluyveromyces lactis and Geotricum candidum were used as test organisms separately in the experiments. Yoghurt milk, following heat treatment, was divided into five parts and the first one was used for the production of reference sample. The remaining four parts were inoculated with Kluyveromyces lactis H-8583 or Geotricum candidum 1 to give the concentrations of 105 cfu/ml and 104 cfu/ml, respectively. Biopreservative culture was also added to the three of those parts at levels of 1, 5 and 10 units, respectively. All parts of the milk were inoculated with 2% of yoghurt starter culture and fermented at 42°C until pH 4.7. The counts of yeast/mould and yoghurt bacteria were determined on days 1, 7 and 15 in the samples stored at 4±1°C. The biopreservative culture has been shown to have a bacteriostatic effect on the growth of Kluyveromyces lactis H-8583 or Geotricum candidum 1 in yoghurt. With the level of 5 units per 50 l of milk, both of the test organisms inhibited the contaminant microorganisms more effectively than with the level of 1 or 10 units. But the protective effect of the culture was no longer than 7 days against Kluyveromyces lactis H-8583 and than 15 days against Geotricum candidum 1.
