Fig. 1

Photomicrographs of kefir grains obtained at the unmagnified level (a) and scanning electronic micrographs of the exterior (b–d) and interior (e, f) surface of a kefir grain. The external surface (c, d) shows the prevalence of the bacilli in tight association with a polysaccharide matrix (kefiran). The inside surface shows rod-shaped bacilli growing in association with yeasts (e, f)