PURPOSE: To obtain a fermented milk or a lactic acid bacterial beverage, using a glucose-tolerant lactic acid bacterium capable of manifesting the excellent proliferation even in a yoghurt mix containing a liquid sugar at a high concentration and producible in a short fermentation time at a low cost.

CONSTITUTION: This new microorganism (a strain of lactobacilli) is capable of providing the recognized formation of a colony when a 10% skimmed milk powder agar culture medium containing ≥16% liquid sugar is smeared with a microbial cell and the culturing is carried out at 37°C for 48 hr. The microorganism belongs to a Streptococcus thermophilus variant strain and named Streptococcus thermophilus OLS 3058 and stipulated as FERM-P No. 13720 in the National Institute of Bioscience and Human-Technology of the Agency of Industrial Science and Technology. This fermented milk or lactic acid bacterial beverage is produced by inoculating a mixed microorganism of this variant strain with a lactic acid bacterium of the genus Lactsbacillus as a starter into a milky raw material and fermenting the mixed microorganism.