Peer-Reviewed Journal Details
Mandatory Fields
Gethins L;Rea MC;Stanton C;Ross RP;Kilcawley K;O'Sullivan M;Crotty S;Morrissey JP;
2016
August
Fems Microbiology Letters
Acquisition of the yeast Kluyveromyces marxianus from unpasteurised milk by a kefir grain enhances kefir quality.
Validated
WOS: 10 ()
Optional Fields
363
16
Kefir is a fermented milk beverage consumed for nutritional and health tonic benefits in many parts of the world. It is produced by the fermentation of milk with a consortium of bacteria and yeast embedded within a polysaccharide matrix. This consortium is not well defined and can vary substantially between kefir grains. There are little data on the microbial stability of kefir grains, nor on interactions between microbes in the grain and in the milk. To study this, a grain was split, with one half of each stored at -20C and the other half passaged repeatedly in whole unpasteurised milk. Grains passaged in the unpasteurised milk recovered vigour and acquired the yeast Kluyveromyces marxainus from the milk which was confirmed to be the same strain by molecular typing. Furthermore, these passaged grains produced kefir that was distinguished chemically and organoleptically from the stored grains. Some changes in ultrastructure were also observed by scanning electron microscopy. The study showed that kefir grains can acquire yeast from their environment and the final product can be influenced by these newly acquired yeasts. Kluyveromyces marxianus is considered to be responsible for some of the most important characteristics of kefir so the finding that this yeast is part of the less stable microbiota is significant.
1574-6968
10.1093/femsle/fnw165
Grant Details