The results of evidence-based analyses from human studies and animal models have shown the clinical potential of probiotics against many diseases. Probiotics have been reported to suppress diarrhea, alleviate lactose intolerance and postoperative complications, exhibit antimicrobial and anti-colorectal cancer activities, prevent inflammatory bowel disease, and reduce irritable bowel symptoms. However, generalizations concerning the potential health benefits of probiotics should not be made because probiotic effects tend to be strain specific. Thus, the health benefit attributed to one strain is not necessarily applicable to another strain even within one species.

To cope with this responsible mission, probiotics must be from carefully selected strains. Lactic acid bacteria with proven beneficial properties and probiotic potential need to be scientifically characterized as they are strain-specific and only by combining these well-selected crops the desired health benefits can be achieved.

The positive effect of probiotics based on living organisms is realized through the normalization of microbial ecology at the expense of:

• inhibiting the growth of potentially harmful microorganisms as a result of the production of antimicrobial substances;  competition with them for adhesion receptors and nutrients;
• stimulating the growth of endogenous microflora as a result of the production of vitamins and other growth-promoting factors;  pH normalization;  neutralization of toxins;
• alteration of microbial metabolism, manifested in increasing or decreasing the activity of enzymes, secretion of various metabolites with a key role in homeostasis and the functions of many organs and systems.