Abstract: A novel method for controlling culture of lactic bacteria, which enables the state of bacteria to be controlled in a simple and rapid manner in the step of cultivation in the production of various products utilizing lactic bacteria. The method is characterized in that, in the step of cultivating lactic bacteria, the intensity of the infrared absorption assignable to dissociable lactic acid and that of the infrared absorption assignable to nondissociable lactic acid in the culture are measured by FT-IR spectrometry and the pH value of the culture and/or the lactic acid concentration of the culture are calculated based on the measurements. The method according to another embodiment is characterized in that, in the above method for controlling culture of lactic bacteria, the intensity of the infrared absorption assignable to glucose as a substrate or an alcoholic C-O group of lactose is measured and the glucose concentration or lactose concentration is calculated based on these measurements.

Abstract: A lactic acid fermented food is sweetened using aspartame alone or a sweetening agent containing aspartame. The lactic acid bacteria which are used to manufacture the lactic acid fermented food and which remain in same are those selected from group A consisting of: Streptococcus cremoris, Streptococcus lactis, Streptococcus diacetilactis, Streptococcus thermophilus, Pedicoccus cerevisiae and Leuconostoc cremoris, and are never those selected from group B consisting of: Lactobacillus bulgaricus and Lactobacillus helveticus.