You may have heard about probiotics but weren't really sure what role they play in food and our health. Probiotics are “good” bacteria that can be found in foods, beverages and supplements. They are used in the preparation of fermented dairy products such as yogurt, buttermilk and kefir. Lactobacilli and bifidobacteria are most commonly used. In addition to probiotics being used in the fermentation process, they are now being added to other foods, such as cheese.