When you think of bacteria your first thoughts maybe of disease and sickness, but some bacteria are necessary for human health and can even help prevent disease. These bacteria are known as probiotics. The word probiotic, literally means "for life." These good bacteria that outnumber human cells 10 to 1 live inside the human gut and have been studied for their immune boosting effects as well as their ability to treat and prevent diarrhea and certain gut related syndromes, including Crohn's and IBS. Foods rich in good bacteria include kefir, yogurt, miso soup, kombucha tea and fermented foods.

Kefir

Though yogurt may be the most well-known source of probiotics, kefir is actually a better source of the healthy bacteria, with three times more probiotic amount present than yogurt. Coming from the Turkish word meaning "good feeling," kefir is a yogurt-like drink made by fermenting milk. The National Kefir Association notes that kefir is an excellent source of protein, fiber and calcium. In addition to being gluten-free and 99 percent lactose-free, kefir is the ideal probiotic-rich beverage for those with lactose or dairy intolerances.

Yogurt

Yogurt, from a Turkish word meaning "to curdle" or "to thicken," is produced by fermenting milk with lactic acid bacteria. Different varieties of bacteria can be used to provide varying consistency and taste to different types of yogurt. Typically, between two and six different strains of bacteria are used. The result is a thickened, probiotic-rich food that possesses a longer shelf life than milk.

Miso Soup and Kombucha Tea

Miso soup is a Japanese dish that consists of tofu and vegetable broth soup. In addition to being high in probiotics, miso soup is also a good source of protein and it's relatively low in calories. Produced by fermenting sweet black tea with a flat culture of yeasts and bacteria, known as the "kombucha mushroom," kombucha tea is a probiotic rich beverage often promoted for detoxification and immune enhancement, according to the American Cancer Society.

Fermented Foods

Like yogurt, kefir, fermented soy used in miso soup and fermented mushrooms used in kombucha tea, other foods can be fermented as well. According to fermentation expert Sandor Katz, foods that are fermented by lactic acid bacteria can be thought of as probiotics. Two examples of fermented vegetables include sauerkraut, which is made by fermenting cabbage and pickles, which are made by fermenting cucumbers.