Lactic acid bacteria is a broad functional group of Gram-positive, low-GC, acid-tolerant bacteria characterized by their metabolic capability to produce lactic acid as the primary end product of carbohydrate fermentation. Academic research focused on this concept investigates their diverse taxonomy, physiological characteristics, genetic mechanisms, ecological roles in various environments (including food systems and biological microbiomes), and their significant applications in food production, preservation, and health, particularly as probiotics.