It may come as a surprise to some that certain kinds of bacteria, such as those found in yogurt, are actually beneficial rather than harmful. Different types of bacteria in yogurt commonly include Lactobacillus bulgaricus, Streptococcus thermophilus, and, in some cases, Lactobacillus acidophilus, Lactobacillus casei, and bifidobacteria. Yogurt has been eaten for so long that no one is really sure how the idea of introducing bacteria to milk in order to produce this rich, tangy food first came about. What is certain, however, is that the bacteria in yogurt perform some important functions, from creating yogurt’s unique taste and texture to promoting a number of health benefits in its consumers.
Evidence suggests that yogurt has been eaten since at least 500 BCE, and it is believed that two types of bacteria have been involved in yogurt production since ancient times. These bacteria are Lactobacillus bulgaricus and Streptococcus thermophilus. When added to milk, these bacteria begin to feed on lactose, a sugar found in dairy products, and subsequently produce lactic acid. It is not known how these bacteria initially found their way into milk, though some suspect the process may have first occurred accidentally. Regardless, the lactic acid produced by the bacteria proved highly useful to ancient peoples, as it allowed dairy products to remain fresh longer than usual.
Since the early 2000s, many yogurt manufacturers in the US and Europe have mounted advertising campaigns drawing public attention to the bacteria in yogurt. The bacteria referred to in such campaigns are often supplemental to the two types of bacteria which have always been found in yogurt. These supplemental bacteria can include Lactobacillus acidophilus, Lactobacillus casei, and bifidobacteria. Collectively, these bacteria are often referred to as probiotics, a term which alludes to the range of health benefits they are believed to promote.
Indeed, in addition to creating a thick texture and a pleasingly tangy taste, the bacteria in yogurt are believed by many medical experts to benefit health in several ways. First of all, by breaking down lactose, these bacteria perform a function with which lactose-intolerant individuals struggle. As a result, yogurt is often tolerated better than other dairy products by the lactose intolerant, and can thus be an important source of calcium and protein. The bacteria in yogurt are also believed to promote a healthy bacterial balance in the intestines, in turn improving digestive health. Finally, the bacteria may help prevent yeast infections in women.