Probiotic food is that containing bacteria or yeasts that can be beneficial for health.
Yoghurt is not probiotic because the bacteria it contains (Streptococcus thermophilus and Lactobacillus bulgaricus) is already dead when it reaches the intestinal tract. However, other dairy products containing Bifidobacterium bifidum or the Lactobacillus casei are probiotic. In addition, fermented non-dairy products such as miso or tempeh can have a probiotic effect.
Yoghurt has in common with probiotic food that the bacteria that transforms the milk generates lactic acid. The acidity helps prevent harmful bacteria proliferate in the intestines.
Other benefits attributed to probiotic food are the strengthening of the inmune system, the prevention of colon cancer or a reduction in the cholesterol levels, though there is little information about such effects. From another side, some effects are related only to certain probiotic microbes.