Here is a beverage with a bacterial boost: L. acidophilus, S. thermophilus, Bifidobacteria, and L. casei to be exact. The bottle contains only 1/2 cup of peach-flavored drinkable yogurt. The consistency resembles that of milk, but the taste is 100% sweet & sour yogurt.
Like the Denmark candies, this drink's label does not give the quantity of bacteria. Based on my personal experience, however, it clearly contains enough bacteria to do something. Perhaps something delightful is happening inside my GI tract, but outside my body the effects are not so pleasant.
The bearded man on the label, Metchnikoff, is credited for suggesting that bacteria may have useful effects on the GI tract. He won a Nobel Peace Prize in 1906 for discovering phagocytosis, the process important to white blood cells. However, he did not actually study probiotics. Another scientist, a Japanese man named Minoru Shirota, took Metchnikoff's idea and spent his life creating a unique bacterium that could thrive in the GI tract.
In 1935 Shirota created a milk beverage called Yakult that contained his healthy bacterium. This drink is available worldwide. Korea's "Metchnikoff Life" must be a variation on the Yakult theme. It's no surprise, then, that the shelves contain so many probiotic beverages: they've been commonplace here for 73 years!