Probiotics are a class of active microorganisms that work by improving the balance of the host's intestinal microflora, and can produce definite health effects to improve the host's microecological balance and play a beneficial role. Probiotics are closely related to our human health and longevity. Delicious foods that people have been eating for thousands of years, such as yogurt, kimchi, sauerkraut, tempeh, natto, kombucha, etc. are all probiotic foods.