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Lactococcus lactis ssp. lactis is one of the most important starter bacteria used in dairy technology and it is of great economic importance because of its use in the production of dairy products, including cheese, butter, cream, and fermented milks. Numerous studies have evaluated the biochemical and probiotic properties of lactococci; however, limited studies on the probiotic characteristics of lactococci were conducted using strains originating from raw milk and dairy products. Characterizing the probiotic properties of strains isolated from raw milk and fermented milk products is important in terms of selecting starter culture strains for the production of functional dairy products. In this study, biochemical properties (including antibiotic sensitivity, lipolytic activity, amino acid decarboxylation, antioxidant activity) and probiotic properties (including antimicrobial activity, growth in the presence of bile salts, bile salts deconjugation, and hydrophobicity) of 14 Lactococcus lactis strains isolated from raw milk and kefir grains were investigated. Strains originating from kefir grains had better characteristics in terms of antimicrobial activity and bile salt deconjugation, whereas strains from raw milk had better hydrophobicity and antioxidant activity characteristics. None of the strains were able to grow in the presence of bile salt and did not show amino acid decarboxylation or lipolytic activities. Biochemical and probiotic properties of L. lactis strains varied depending on the strain and some of these strains could be used as functional cultures depending on their properties. However, these strains did not possess all of the properties required to meet the definition of a probiotic.

In this research, effect of bee pollen supplement on antimicrobial, chemical, rheological, sensorial properties and probiotic viability of fermented milk beverages was studied. Bee pollens were added in the rate of 2.5 mg•mL-1 (B), 5 mg•mL-1 (C), 7.5 mg•mL-1 (D), 10 mg•mL-1 (E), and 20 mg•mL-1 (F). Control sample (A) was not supplemented with bee pollen. Control and supplemented milk samples were fermented by a commercial ABT1 starter culture (Chr. Hansen, Hørsholm, Denmark) containing Lactobacillus acidophilus La 5, Bifidobacterium animalis subs. lactis Bb 12, and Streptococcus thermophilus. While no antimicrobial impact was observed against L. monocytogenes, S. aureus, P. fluorescens, P. aeruginosa and A. hydrophilia upto 7.5 mg•mL-1 pollen addition, addition between 10 mg•mL-1 to 20 mg•mL-1 resulted in activity, and positive effect only in inhibition rates against bacteria such as S. thyphimurium and E. coli. Bee pollen supplements has shown a positive effect on probiotic viability and occurred on increase apparent viscosity, but their effect on sensorial properties was negative. Furthermore an improvement with increasing concentration of pollen addition that yielded no negative effect on physicochemical properties was detected.

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The study investigated the potential use of Enterococcus faecium and E.durans strains as adjunct cultures in the production of set-type probiotic yoghurt. There were significant changes and differences in the pH, titratable acidity, textural properties and microbiological properties of the products containing adjunct culture during the storage period (P < 0.05), whereas there were no statistically significant differences between the sensory properties (P > 0.05). In conclusion, the use of Enterococcus species that have known probiotic properties as the adjunct culture in yoghurt production can also positively affect the physical, chemical and rheological properties in addition to its positive effects to the functional properties by increasing the viable probiotic bacterial counts.