Title of English Abstract Evaluating probiotic properties of Lactobacillus species in curdled milk

The main purpose of this study was to investigate the probiotic properties of lactobacilli including fermentability, acid and bile tolerance, bile salt hydrolysis, and hemolytic properties, antibiotics and antimicrobial activities and bacteriocin production from curdled milk samples. Method: Among the total bacterial isolates, seven isolates were confirmed to be lactobacilli through examining morphological characteristics, biochemical tests and by means of ۱۶S rDNA method. Results:LAB E showed the highest resistance to acidic environment. Also, in bile condition the number of LAB B and D colony significantly reduced from about ۱۰۷ to ۱۰۲ after ۱ hour and to less than ۱۰۰ after ۲ and ۴ hours. As well none of the strains showed any sensitivity towards fungal and microbes except for Escherichia coli which all strain was sensitive to . Conclusions:Based on this study results, LAB E and C isolated from cow milk enzymatic curdled from some area of Varamin, Karaj and Damavand could be considered as probiotic microorganism considering the observed properties. They could be isolated in order to be used in the production of probiotic dairies.

Keywords:

Probiotic , Lactic acid bacteria , Crude milk , Milk