Do all fermented foods contain a probiotic?

One of the most common myths about probiotics is that they’re often found in traditional fermented foods. In reality, however, the microorganisms in fermented foods rarely qualify as probiotics because they’re present in unknown or unstandardized types and amounts. True probiotics must have defined microbial strains and amounts, and have scientific evidence linking them with a health benefit. Occasionally, fermented foods such as yogurts not only use microbes for fermentation but also have probiotics added after fermentation to provide a specific health benefit.