Preliminary evaluation of probiotic properties and safety profile of isolated from spontaneously fermented milk, .

The aim of this study was to assess the probiotic potential and safety profile of a EGER41 strain isolated from Kenyan spontaneously fermented milk, . The . EGER41 isolate was tested for temperature sensitivity (at 15 °C, 30 °C, 37 °C, and 45 °C), pH tolerance (at 2.0, 2.5, 3.0, 3.5, and 6.5 as control), and 0.4% phenol tolerance to observe its survival in the gastrointestinal tract of humans. For safety evaluation of the isolate, antagonistic activity was tested against pathogenic strains of , serovar Typhi, and , while antibiotic susceptibility pattern was examined using nalidixic acid, ampicillin, azithromycin, ciprofloxacin, tetracycline, gentamicin, and chloramphenicol antibiotic discs and haemolytic activity was done using lamb blood agar. The isolate had an optimal growth at 37 °C, it also demonstrated low pH tolerance (2.0-3.5). It was able to maintain its viability (∼100%) after exposure to 0.4% phenol. The selected isolate showed inhibition (antagonistic activity) against the pathogens with having the largest (ZDI = 31.0 ± 1.73 mm) zone of diameter inhibition (ZDI) and having the least (ZDI = 18.0 ± 0.76 mm). isolate was sensitive to Azithromycin, tetracycline and chloramphenicol and was intermediately sensitive to gentamycin, while it was resistant to nalidixic acid, ampicillin, and ciprofloxacin. The isolate also exhibited γ-haemolytic activity hence safe for use as a starter culture and was identified as a EGER 41 strain based on 16S rRNA gene sequencing. The selected isolate can potentially be used as a starter culture and a probiotic since it had excellent probiotic properties.