Probiotic bacteria are found mainly in fermented foods, a sourdough starter when it is alive is a probiotic. There are many studies that promoting a positive health image of probiotics in fermented foods such as sauerkraut, yogurt and kefir for example.
Fermented foods contain living microorganisms (bacteria), however there are many questions about the ability of the probiotics to survive and become active when entering the consumer’s gastrointestinal tract. The general consensus is that probiotics, when consumed as part of a fermented food are beneficial.