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。

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BAS light Liquid sourdough produced through a completely natural multistage fermentation process. Specially elaborated for the production of all types of dark and light bread.

通过多次纯天然发酵过程制作而成的液体酸面团添加剂，适用于制作各种欧式酸面包。

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He made everything - except coffee - from sourdough, a substance used in making sourdough bread.

VOA: special.2009.01.24

The worst offender: Applebee's grilled cheese sandwich on sourdough bread with fries and 2% chocolate milk.

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The store was also a very strong food outlet, featuring specialty items such as real sourdough bread, whole coffee beans etc.

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It dishes up authentic Polish cuisine with an international twist, along the lines of beef stroganoff with chanterelle mushrooms served in a hollowed-out loaf of sourdough bread, and saddle of roe deer marinated in red wine and served with blueberry jelly.

BBC: A taste of Krakow