probiotics are live micro-organisms (bacteria or yeasts), added as supplements to certain food products, such as yogurts or cereals for example, which have a beneficial effect on health by helping to fiber digestion, stimulating the immune system while preventing or treating digestive disorders.

Probiotics are beneficial microorganisms that colonize the intestinal and vaginal flora. Their presence makes it possible in particular to counter the proliferation of harmful micro-organisms which can, for example, cause infectious diarrhea or vaginitis. Probiotics also aid in the digestion of food.

Probiotics act through three main mechanisms:
- Modulate the activity of the intestinal immune system
- Increase the barrier function of the intestinal mucosa
- Finally , probiotics have direct antimicrobial effects, mainly by inhibiting the invasion of pathogenic bacteria and their adhesion to the intestinal walls.

Lactic acid bacteria are among the main probiotics and are generally used to produce yogurt, sauerkraut, lacto-fermented vegetables and salami