Abstract: Yogurt containing lactic acid bacteria and Bifidobacteria, to which one or more kinds of sweet substances selected from a group consisting of palatinose, palatinite, maltose, maltitol, starch syrup, reducing starch syrup and trehalose as well as a refined fish oil containing highly unsaturated fatty acids such as DHA and EPA are added, is packed in an oxygen blocking hermetic package. The yogurt contains highly unsaturated fatty acids and has good flavor and taste, as well as excellent product quality stability, and does not generate a fishy odor during normal storage periods.

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.