The present invention relates to a bacterium of the species Lactobacillus fermentum, wherein the bacterium is characterized in that it increases the pH of a fermented milk product comprising the Lactobacillus fermentum during storage after fermentation in comparison to a milk product fermented with the same starter culture not containing the Lactobacillus fermentum. In a related embodiment the present invention provides a bacterium of the species Lactobacillus fermentum characterized in that a fermented milk product comprising the Lactobacillus fermentum maintains a pH above 4.0 when stored for at least 14 days at 25° C., wherein the fermented milk product is obtained by a method comprising incubating a milk with the Lactobacillus fermentum in a concentration of at least 107 CFU/g and with a starter culture, fermenting until a pH of 4.6 is reached, shaking the fermented product and cooling. The invention further relates to compositions comprising the bacteria, methods for producing fermented milk products using the bacteria and the products thus obtained.
