The scope of the experiments included analysis of the antimicrobial activity of ethanolic, methanolic and aqueous extracts against bacterial and fungal cultures and determination of the minimum inhibitory concentration of plant extracts tested microbial growth. Analysis of the antifungal and antibacterial activity was carried out by the disc diffusion method using paper discs. In the experiment 11 species of microorganisms - 8 bacterial and 3 fungal strains were used. The highest antimicrobial activity against the tested strains was demonstrated by black elder (Sambucus nigra L.), black locust (Robinia pseudoacacia L.) and lingonberry (Vaccinium vitis-idaea L.) extracts. The study showed the diverse morphological activity of specific parts of elderberry and quince, which is the effect of different polyphenolic profile of these plants. The yeast Saccharomyces cerevisiae, Escherichia coli, Pseudomonas putida and Bacillus subtilis showed the highest sensitivity to the effect of extracts of the analysed plants. As a positive control three antibiotics - amphotericin B, vancomycin and amoxicillin with clavulanic acid were used.

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The aim of the study was to characterise, quantitatively and qualitatively, the yeast microbiota found during spontaneous fermentation of grape musts obtained from the red grape varieties 'Rondo' and 'Regent'. For the research, grapes originating from two vineyards (Srebrna Góra and Spotkaniówka) located in southern Poland were used. Musts of the studied grape varieties provided a favourable environment for the growth of microorganisms. Musts obtained from fruits from the Spotkaniówka vineyard were characterised by a higher overall number of yeasts. A maximum number of cells were recorded from the fourth to the ninth day of the process, in all of the analysed musts. The growing season of 2013 proved to be the least favourable for the growth of microorganisms on grapes, which resulted in their smaller number in the batches during spontaneous fermentation. During the process, succession of different groups of yeasts was observed. It was initiated by Hanseniaspora uvarum and Candida railenensis strains, which, with the progress of spontaneous fermentation, were replaced by Saccharomyces cerevisiae strains. Metschnikowia pulcherrima and Pichia membranifaciens yeasts were identified at both the beginning and the end of the process. During fermentation, Zygoascus meyerae, Kluyveromyces lactis and Nakazawaea ishiwadae strains were also identified.

Biodiversity of native yeasts, especially in winemaking, has hidden potential. In order to use the value of non-Saccharomyces strains in wine production and to minimise the possibility of its deterioration, it is necessary to thoroughly study the yeast cultures present on grape fruits and in grape must, as well as their metabolic properties. The aim of the study was to characterise the yeast microbiota found during spontaneous fermentation of grape musts obtained from grape varieties 'Rondo', 'Regent' and 'Johanniter'. Grapes from two vineyards (Srebrna Góra and Zadora) located in southern Poland were used for the research. Succession of subsequent groups of yeasts was observed during the process. Metschnikowia pulcherrima yeasts were identified both at the beginning and the end of the process. Hanseniaspora uvarum, Wickerhamomyces onychis and Torulaspora delbrueckii strains were also identified during the fermentation. Torulaspora delbrueckii and Wickerhamomyces onychis strains were identified only in grape musts obtained from grapes of the Zadora vineyard. These strains may be characteristic of this vineyard and shape the identity of wines formed in it. Our research has provided specific knowledge on the biodiversity of yeast cultures on grapes and during their spontaneous fermentation. The research results presented indicate the possibility of using native strains for fermentation of grape musts, allowing to obtain a product with favourable chemical composition and sensory profile.

Sauerkraut is the most important fermented vegetable obtained in Europe. It is produced traditionally by spontaneous fermentation of cabbage. The aim of this study was to determine biodiversity of yeasts present during fermentation of eight varieties of cabbages (Ambrosia, Avak, Cabton, Galaxy, Jaguar, Kamienna Głowa, Manama and Ramco), as well as characterize obtained yeast isolates. WL Nutrient Agar with Chloramphenicol was used to enumerate yeast. Isolates were differentiated using RAPD-PCR and identified by sequencing of the 5.8S-ITS rRNA gene region. The volatiles production was analyzed using SPME-GC-TOFMS. Our research confirmed that during sauerkraut fermentation there is an active growth of the yeasts, which begins in the first phases. The maximal number of yeast cells from 1.82 to 4.46 log CFU g−1 occurred after 24 h of fermentation, then decrease in yeast counts was found in all samples. Among the isolates dominated the cultures Debaryomyces hansenii, Clavispora lusitaniae and Rhodotorula mucilaginosa. All isolates could grow at NaCl concentrations higher than 5%, were relatively resistant to low pH and the presence of lactic acid, and most of them were characterized by killer toxins activity. The highest concentration of volatiles (mainly esters and alcohols) were produced by Pichia fermentans and D. hansenii strains.