Bacteria which produce putrefaction and gas in the intestines cannot live in lactic acid.

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Gruber knew all this, but he also knew that some lactobacilli, the bacteria used to make yogurt, naturally excrete just the left-handed version of lactic acid.

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First, a source of starch or sugar, which could be an agricultural by-product, is fermented to produce lactic acid the same substance made by the body during exercise, only in this case it comes from the bacteria exercising themselves in the fermentation process.

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