Mary

“Mindful yogurt manufacturers often use bacteria that produce more dextrorotatory (right-turning) than levorotatory (left-turning) lactic acids. Molecules of the two kinds of lactic acid are mirror images of each other. Feeding the human digestive system with levorotatory lactic acid molecules is like giving a left-handed pair of scissors to a right-handed person: they’re hard to handle. That is why it is a good idea to pick yogurt from the supermarket shelves that states on the container: “Contains mainly dextrorotatory [or right-turning] lactic acid.”
― Giulia Enders, Gut: The Inside Story of Our Body’s Most Underrated Organ