Lactic Acid Bacteria

Lactic acid bacteria (LAB) are an order of gram-positive, low-GC, acid-tolerant, typically nonsporulating, nonrespiring, either rod-shaped (bacilli) or circular (cocci) bacteria that share common metabolic and physiologic characteristics. These pathogens, mostly found in decomposing plants and milk products, produce carboxylic acid because the dominant metabolic outcome of carbohydrate fermentation. This habit has, throughout history, linked LAB with food fermentations, as acidification inhibits the expansion of putrefaction agents. Proteinaceous bacteriocins are produced by several LAB strains and supply a further hurdle for wrecking and pathogenic microorganisms. Furthermore, carboxylic acid and other metabolic amounts contribute to the organoleptic and textural portrait of a food item. the economic importance of the LAB is further evidenced by their generally recognized as safe (GRAS) status, thanks to their omnipresent appearance in food and their contribution to the healthy microbiota of animal and human mucosal surfaces. The classification that comprise the LAB are at its core Lactobacillus, Leuconostoc, Pediococcus, Lactococcus, and Streptococcus, also because the more peripheral Aerococcus, Carnobacterium, Enterococcus, Oenococcus, Sporolactobacillus, Tetragenococcus, Vagococcus, and Weissella; these belong to the order Lactobacillales.