Selection, Molecular Identification and Testing of Potentially Probiotic Bacteria Recovered from Popular Artisanal Egyptian Cheeses

Abstract

The present study was aimed to select potential probiotic and functional strains among lactic acid bacteria (LAB) isolated from some artisanal Egyptian dairy products. For this, 75 samples comprising karish (fresh skimmed), mish (aged salted skimmed) and Domiati (brined ripened) cheese varieties were surveyed in this study. Approximately, 300 lactic acid bacterial (LAB) strains were isolated and initially screened for their antibacterial activity against the two common food-borne pathogens; Staphylococcus aureus and Escherichia coli O157:H7. Using cell free extract of isolated LAB strains, various antimicrobial inhibition patterns have been noted against the tested pathogens. Upon further proteolytic and neutralization treatments, only 16 strains were proved to have potent antimicrobial attribute. Based on 16S rRNA gene sequencing identification of those 16 strains, 8 different species were identified (Lactobacillus plantarum, Lb. fermentum, Pediococcus acidilacticii and Enterococcus faecium). Additionally, those 16 strains were tested for different probiotic, functional and safety criteria (acid and bile resistance, salt tolerance, milk acidification ability, heamolytic activity and antibiotic sensitivity).  The present study showed that artisanal Egyptian artisanal chesses were proven to be sources of safe potentially probiotic LAB with interesting physiological properties, thus it could be further incorporated in manufacture of various dairy products as starter and non-starter cultures.