Sourdough bread is a fermented bread which contains lactic acid bacteria and so does fermented soy.

酵母面包是一种发酵了的面包，它含有乳酸菌，发酵大豆中也含有乳酸菌。

youdao

Legend has him eating peasant food--cabbage soup, cabbage soup, porridge, meat with pickled cucumbers, ham and cheese, and kvass, which is a drink that I've actually tasted from fermented black bread.

据传他爱吃农家食物,诸如卷心菜汤,稀粥,腌黄瓜拌肉,芝士火腿和克瓦斯,这种酒由发酵的黑面包做成,我曾经尝过

youdao

You ate no bread and drank no wine or other fermented drink.

你们没有吃饼，也没有喝清酒浓酒。

youdao

Legend has him eating peasant food--cabbage soup, cabbage soup, porridge, meat with pickled cucumbers, ham and cheese, and kvass, which is a drink that I've actually tasted from fermented black bread.

据传他爱吃农家食物,诸如卷心菜汤,稀粥,腌黄瓜拌肉,芝士火腿和克瓦斯,这种酒由发酵的黑面包做成,我曾经尝过

耶鲁公开课 - 欧洲文明课程节选

The son writes that every miner's cabin had a "tin full of fermented dough, used in place of yeast in making bread, biscuits and flapjacks" hanging over the hot stove.

NPR: Sourdough: More than a Bread