The possible beneficial properties of food and associated microorganisms for both human and animal
health are increasingly investigated. While many bacteria have been characterised as probiotics, only one
yeast variety, Saccharomyces cerevisiae var. boulardii, has been recognised to be part of this group,
regardless of the importance of yeasts in the food industry. In this work, we have studied the probiotic or
health-beneficial potential of 130 yeast strains isolated from food belonging to the collection of the
Institute of Food Science Research CIAL (CSIC-UAM). To that end, the response of these yeasts to physiological
conditions during consumption has been assessed through measuring their capacity to grow at
37 C and to survive the gastrointestinal transit conditions. Almost 50% of the yeast analysed could thrive
at the host intestine temperature, and of these, almost 37% had growth kinetic parameters higher at 37 C
than at 25 C. In addition, about 95% of the strains could survive the exposition to conditions simulating
the gastrointestinal transit. The yeast strains were also analysed for exhibiting auto-aggregation
phenotype, antioxidant activity and the production of killer peptides, this only found in 8.5% of the
strains analysed. These properties could be regarded as additional interesting features for selecting new
probiotic strains.