Ragusana donkey milk as a source of lactic acid bacteria and yeast strains of dairy technological interest

Donkey milk is considered an interesting substitute to cow’s milk thanks to its nutritional properties. The chemical composition of donkey milk has been extensively considered essential to prevent the growth of undesirable microorganisms, and few data are available on its microbiological characterization. In the present study raw and cultured donkey milk samples were analyzed in order to characterize lactic acid bacteria and yeast populations. Both lactic acid bacteria and yeast isolated strains were identified using a combination of different molecular techniques and results were confirmed by sequence analysis of the 16S rRNA gene and ITS regions, respectively. Furthermore, technological traits of the strains were investigated. The results indicated that dominant lactic acid bacteria strains were identified mainly as Lactococcus lactis subsp. lactis/cremoris and Lactobacillus paracasei. The strains showed both good coagulant and acidifying activities and 50% of them was able to grow in presence of 5.0 g/l of lysozyme. Among isolated yeast strains, the 70% was ascribed to the Kluyveromyces lactis species. The results of present study indicated that Ragusana donkey milk is an interesting source of lactic acid bacteria and yeast strains of technological interest.