###### Abstract  
In the last decade, probioticate yeasts have gained more attention from the scientific community. However, over the decades, researchers have mostly viewed spoilage yeasts as unnecessary and unwanted contamination without considering any of their potentially positive properties. This often led to oversights and the loss of many potentially interesting yeast strains. In this study, we have screened multiple spoilage yeast strains from various spoiled food products and assessed their potential as probiotic candidates. Within this research, we identified two promising probiotic candidates, 113_Metsch_pulcherrina and 101_Pich_kudriavzevii.  
probiotic yeasts; spoilage yeasts; food microbiology; _Metschnikova pulcherrina; Pichia kudriavzevii_; antioxidant activity; gastrointestinal survival; autoaggregation  
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yeast strains they have isolated from various fermented foods of plant origin. This group includes _Saccharomyces cerevisiae_ strains isolated from spontaneously fermented wines [6; 7], fermented olives [8], Indian traditional fermented foods [9], kombucha [10], Ethiopia fermented foods [11], the fermented rice beverage Chhang [12], and traditional Turkish soundough [13]. On the other hand, non-Saccharomyces yeasts are becoming the object of increasing interest. The literature contains reports on the isolation and study of the potential probiotic properties of yeasts, including the following: _Candida orthoposilosis_, _C. tropicalis_, _Debaryomyces hansenii_, _Meyerozyma carribica_, _Pichia guilliermodii_ from fermented olives [8], _M. carribica_ from pineapple [14], _Hansenispora opuntiae_, _P. kudriavzevii_, and _Wickerhamomyces anomaluss_ from spontaneously fermented guajillo peppers [15], _P. kudriavzevii_ from kombucha [10], _Candida hunilis_ and _P. kudriavzevii_ from Ethiopian fermented foods [11], _Meyerozyma guillernondii_ and _M. caribbica_ from Indian traditional fermented products [16], _Diutta (Candida) mesorgosa_ from tempeh [17], _P. kudriavzevii_ from shalgam, and _W. anomalous_s from olive brine [13]. There are also reports of obtaining potentially probiotic yeasts from foods of animal origin, e.g., _P. kudriavzevii_, _P. fermentans_, and _Yarrowia lipolytica_ isolated from raw milk [18], _Kluyveromyces lactis_ from cheese, _Toruspora delbrueckii_ from kefir [13], and _S. cerevisiae_ and _K. marxianus_ from kefir [19; 20]. Many of the above-mentioned species of potentially probiotic yeasts can cause negative changes in food products during uncontrolled fermentation, which means they can be treated as spoilage factors [2; 3]. All the above-mentioned authors used similar screening procedures for testing probioticticity in vitro, consisting of the following analyses: growth at human body temperature, survival in the gastrointestinal tract, ability to colonise mucosal surfaces, antimicrobial and antioxidant properties, antibiotic resistance, as well as cell surface properties (hydrophobicity, autoaggregation, and co-aggregation ability). Determining the safety of the tested yeast candidates (no pathogenicity or ability to produce hazardous metabolites) is also an important aspect [21]. This approach has made it possible to obtain several satisfactory isolates from among the dozen or more strains isolated.  
In this research, we decided to go against the mainstream trend of fighting to reduce spoilage yeasts and instead focus on screening their probiotic properties and potential. The aim of this study was to obtain yeast isolates from various food products of plant origin, where fermentation was undesirable, and perform in vitro testing for potential probiotic and safety characteristics.