Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics.

Production of lactic acid has linked LAB with food fermentations, as acidification inhibits the growth of spoilage agents.

Proteinaceous bacteriocins are produced by several LAB strains and provide an additional hurdle for spoilage and pathogenic microorganisms.

The industrial importance of the LAB is further evidenced by their generally recognized as safe (GRAS) status, due to their ubiquitous appearance in food and their contribution to the healthy microbiota of animal and human mucosal surfaces.

The genera that comprise the LAB are at its core Lactobacillus, Leuconostoc, Pediococcus, Lactococcus, and Streptococcus, as well as the more peripheral Aerococcus, Carnobacterium, Enterococcus, Oenococcus, Sporolactobacillus, Tetragenococcus, Vagococcus, and Weissella.

[2] Their relative simple metabolism has also prompted their use as microbial cell factories for the production of several commodities for the food and non-food sectors [3] LAB genera are classified in terms of two main pathways of hexose fermentation: Some members of Lactobacillus appear also able to perform aerobic respiration, making them facultative anaerobes, unlike the other members of the order, which are all aerotolerant.

[16] Future applications of probiotics have been conjectured to include delivery systems for vaccines and immunoglobulins, and the treatment of different gastrointestinal diseases and vaginosis.

[15] The quest to find food ingredients with valuable bioactive properties has encouraged interest in exopolysaccharides from LAB.

However, there is a wide variation in molecular structures of exopolysaccharides and the complexity of the mechanisms by which physical changes in foods and bioactive effects are elicited.

Various LAB, largely from genus Lactococcus and Lactobacillus, suppress mycotoxigenic mold growth due to the production of anti-fungal metabolites.

[20] In a study for postharvest food product safety conducted with 119 LAB isolated from the rhizosphere of olive trees and desert truffles, mostly within the genera of Enterococcus and Weissella, researchers found strong antibacterial activity against Stenotrophomonas maltophilia, Pantoea agglomerans, Pseudomonas savastanoi, Staphylococcus aureus and Listeria monocytogenes, and anti-fungal activity against Botrytis cinerea, Penicillium expansum, Verticillium dahliae and Aspergillus niger.

The different availability of enzymes that contribute to the vast spectrum of aromas in wine are associated with glycosidases, β-glucosidases, esterases, phenolic acid decarboxylases and citrate lyases.

Areas of interest in managing this risk include the sources of phage contamination, measures to control their propagation and dissemination, and biotechnological defense strategies developed to restrain them.

A variety of molecules have been suggested to act as host receptors for bacteriophages infecting LAB; among those are polysaccharides and (lipo)teichoic acids, as well as a single-membrane protein.

[28] Dextrans, like other glucan, enable bacteria to adhere to the surface of teeth, which in turn can cause tooth decay through the formation of dental plaque and production of lactic acid.