IngredientsLeuconostoc is a genus of gram-positive bacteria, placed within the family Leuconostocaceae, order Lactobacillales. The name derives from the Greek adjective leukos, meaning "clear," and the word nostoc, referring to gelatinous colonies — effectively meaning "colorless nostoc." Species of the genus are facultatively anaerobic, gram-positive, nonmotile, catalase-negative, asporogenous, psychrotolerant or psychrotrophic bacteria with an optimum growth temperature of 25–30°C and an average GC content of 37.5%.
Members are generally ovoid cocci often forming chains. They are intrinsically resistant to vancomycin and are catalase-negative, which distinguishes them from staphylococci. All species within this genus are heterofermentative and are able to produce dextran from sucrose. Leuconostocs, like other lactic acid bacteria (LAB), do not contain a tricarboxylic acid cycle or a cytochrome system and so cannot derive energy from oxidative phosphorylation.
Taxonomic investigation has covered genome sequences belonging to at least 17 species. According to the latest standing in nomenclature, there are 16 valid species along with 11 synonyms. The most widely studied and industrially important species include Leuconostoc mesenteroides (with subspecies mesenteroides, cremoris, and dextranicum), Leuconostoc pseudomesenteroides, Leuconostoc lactis, Leuconostoc citreum, Leuconostoc kimchii, and Leuconostoc gelidum.
The genus Leuconostoc is phenotypically related to Lactobacillus and Pediococcus and shares many features with the heterofermentative lactobacilli. It often occurs in similar habitats as Lactobacillus and Lactococcus and was historically considered an intermediate between Streptococcus and Lactobacillus. The genus Leuconostoc belongs to the Lactobacillaceae family, also known as lactic acid bacteria.
Leuconostoc is a genus of saccharolytic heterofermentative lactic acid bacteria that inhabit plant-derived matrices and a variety of fermented foods, including dairy products, dough, and milk. They inhabit several food sources, such as vegetables, silage, fruits, meat, fish, and dairy products.
Leuconostoc can often be found in the wild and is part of the natural microflora in almost all farming fields. It is most commonly found in many different processed foods — in sugar processing liquors and fermented foods, including olives, cucumbers, sauerkraut, wine, and cheese — either as a starter culture or as a contaminant.
Leuconostoc spp. are found in a wide variety of habitats, including human and animal gastrointestinal tracts, plant surfaces, dairy fermentations, and fermented vegetables. A few reports of their presence in chilled stored meats and human blood are also documented.
Leuconostoc was first isolated by Cienkowski from a slime outbreak in a sugar factory in 1878. The isolate was named Ascococcus mesenteroides and was characterized by its production of dextran slime in sucrose solutions. In 1911, an aroma bacterium designated "X" was isolated from a creamery starter; it was later formally named Leuconostoc in 1930. Leuconostoc has been known as a component of starter cultures in dairy since the 1920s, though factual documentation of its dairy role remained sparse for many decades.
Leuconostoc has not historically been isolated, identified, or deliberately administered as a dietary supplement in the modern sense. Its traditional uses are inseparable from the fermented foods in which it naturally resides and to which it contributes.
Leuconostoc spp., along with other lactic acid bacteria such as Pediococcus and Lactobacillus, are responsible for the fermentation of cabbage, making it sauerkraut. In this process, fresh cabbage is fermented in a light brine, where the sugars in the cabbage are transformed by lactofermentation to lactic acid, which gives the cabbage a sour flavour and good keeping qualities. Plant fermentations of this kind contain four principal species of lactic acid bacteria: Leuconostoc mesenteroides, L. brevis, L. plantarum, and Pediococcus pentosaceus.
Kimchi, an emblematic traditional food in Korean culture, is made through fermentation of vegetables such as Chinese cabbage and radish seasoned with various spices including red pepper powder, garlic, ginger, green onion, fermented seafood (jeotgal), and salts. Members of the genera Leuconostoc, Lactobacillus, and Weissella are the dominant LAB regardless of the kimchi type or starter inoculation; among the three genera, Leuconostoc is the most abundant, followed by Lactobacillus and Weissella.
Leuconostoc species are used as starter cultures in many soft (unripened cottage cheese), semisoft (Caerphilly), semihard (Gouda), and blue-vein cheeses. Leuconostoc mesenteroides occurs as part of the natural progression of lactic acid bacteria in fermented vegetables, and dextran-producing strains of Leuconostoc can cause serious spoilage problems in sugar processing. They grow in close symbiosis with the Lactococcus population, and their presence is technologically beneficial for the production of aromatic compounds such as diacetyl and acetoin from citrate, the production of gas, and the ability to produce dextrans.
In most traditional African fermented foods there are significant amounts of Bifidobacterium, Enterococcus, Lactococcus, and Leuconostoc. Leuconostoc spp. are LAB familiar to humans, frequently detected in traditional fermented foods, and used industrially as starter bacteria for food fermentation. Strains of L. mesenteroides have also been isolated from Mongolian traditional fermented milk (airag), reflecting the genus's broad historical presence across diverse fermentation cultures.
Leuconostoc spp. are gram-positive and heterofermentative bacteria capable of transforming glucose molecules into carbon dioxide, ethanol, and lactate. These bacteria are used as starter cultures in food and beverage fermentation in order to improve nutritional and organoleptic quality and to extend shelf life. They produce exopolysaccharides (dextran or levan), oligosaccharides, mannitol, bacteriocins, and vitamins.
The exopolysaccharide (EPS) produced by Leuconostoc mesenteroides is a glucan with α-1,6 and α-3,6 branched glycosidic linkages. Structural analyses show that the main backbone of the glucan consists of α-(1→6)-linked D-glucopyranose units, with α-(1→3) branched chains accounting for a smaller fraction. One such bacterium, Leuconostoc mesenteroides, excretes dextran, authorized as a novel food ingredient to be used in bakery products (Decision 2001/122/EC). Besides its technological property as a thickener in bakery and dairy products, prebiotic potentialities have been associated with this polymer, as gut microbes metabolize it to produce propionic acid, which is able to reduce cholesterol and triglyceride levels.
Many L. mesenteroides species generate a variety of organic acids, as well as a class of antibacterial chemicals known as bacteriocins (such as carnosin and leuconocin). These chemical substances inhibit both gram-negative and gram-positive bacteria. Some strains of Leuconostoc spp. produce bacteriocins, and a variety of Leuconostoc bacteriocins have been reported in the last 40 years since the first discovery in 1984.
Metabolite analysis using 1H NMR has shown that kimchi fermented with Leuconostoc mesenteroides starter culture produces greater amounts of lactic and acetic acids and mannitol. These bacteria can produce abundant organic acids (mainly lactic acid) and metabolites; exopolysaccharide (EPS) is one of the important and bioactive compounds among many LAB metabolites.
Their presence is technologically beneficial for the production of aromatic compounds such as diacetyl and acetoin from citrate. These compounds contribute to the characteristic flavors of fermented dairy products.
Prebiotics associated with L. mesenteroides-produced exopolysaccharides (EPS) demonstrate substantial host metabolic benefits. L. mesenteroides-produced EPS is an indigestible α-glucan, and intake of the purified form improved glucose metabolism and energy homeostasis through EPS-derived gut microbial short-chain fatty acids and changed gut microbial composition. These findings reveal an important mechanism that accounts for the effects of diet, prebiotics, and probiotics on energy homeostasis.
In vitro, EPS produced by L. mesenteroides stimulated the growth of several lactic acid bacteria strains, indicating its potential as a prebiotic. In a human gastrointestinal simulator inoculated with fecal microbiota, the EPS favored the growth of Bifidobacterium spp. and lactobacilli while reducing Enterobacteriaceae.
Novel probiotic S. thermophilus and Leuconostoc strains were found to be extremely good inducers of Th1-type cytokines. One of the approaches in treating allergy could be tipping the Th1/Th2 balance from Th2 predominance to a Th1-type response. Probiotic S. thermophilus and Leuconostoc strains are more potent inducers of Th1 type cytokines IL-12 and IFN-γ than probiotic Lactobacillus strains presently in clinical use. Human peripheral blood mononuclear cells (PBMC) offer a model for studying the potential of different probiotic strains to induce cytokine production.
Several studies have shown that L. mesenteroides treatments can exert antioxidant activities, improve immunity, reduce cholesterol levels, and alleviate hyperlipidemia. L. mesenteroides administration was found to effectively reduce levels of the inflammatory factor IL-6, prompting researchers to speculate that L. mesenteroides may serve as a safe immunomodulatory treatment.
EPS from L. mesenteroides displayed significant antibacterial activity against eight foodborne pathogens and inhibited biofilm formation by Listeria monocytogenes. When tested in a mixed culture with Listeria innocua, Listeria ivanovii, or Staphylococcus aureus, certain strains reduced the numbers of these species by 1.87, 1.78, and 1.38 log units, respectively; these strains were found to possess good probiotic properties in vitro and a high capacity for Listeria spp. inhibition in mixed cultures.
In in vitro assays, EPS from L. mesenteroides SJC113 exhibited moderate antioxidant activity (free radical scavenging activity of 10.94 ± 1.33% and hydroxyl scavenging activity of 6.29 ± 1.59% at 1 mg/mL). Notably, it showed high cholesterol-binding activity, lowering cholesterol levels by 40% at 1 mg/mL EPS. Prebiotic potentialities have been associated with dextran from L. mesenteroides, as gut microbes metabolize it to produce propionic acid, which can reduce cholesterol and triglyceride levels. In addition, EPSs have generally been suggested as blood cholesterol reducers, antioxidants, immunomodulators, and antitumor and antiulcer agents.
One preclinical study investigated the alleviating effects of kimchi and Leuconostoc mesenteroides DRC 1506 isolated from kimchi on ulcerative colitis. A freeze-dried kimchi suspension and DRC were orally given to mice at a dose of 1 × 109 CFU/day for 3 weeks, and 3% dextran sulfate sodium (DSS) in drinking water was used to induce colitis. The kimchi and DRC groups reduced symptoms of colitis, such as disease activity index, decrease in colon length, colon weight-to-length ratio, and pathological damage to the colon. The groups also decreased the levels of pro-inflammatory cytokine TNF-α and increased anti-inflammatory cytokine IL-10 in the colon tissues. This evidence is preclinical (murine) only; no controlled human trials specifically examining Leuconostoc in inflammatory bowel disease have been identified in the peer-reviewed literature reviewed here.
One study evaluated the effect of Leuconostoc mesenteroides subsp. mesenteroides SD23 on obesity-related metabolic dysfunction. Mice were randomly divided into four dietary groups: standard diet, high-fat diet (HFD), standard diet with L. mesenteroides SD23, and HFD with L. mesenteroides SD23. Diets were maintained for 14 weeks. HFD induced metabolic dysfunction, increased the number of larger adipocytes, and induced liver TNF-α expression, as well as increased cholesterol, leptin, and glucose levels. The study was conducted in mice; no controlled clinical data in humans specifically on Leuconostoc for obesity were identified.
EPS from L. mesenteroides — an indigestible α-glucan — improved glucose metabolism and energy homeostasis through EPS-derived gut microbial short-chain fatty acids and changed gut microbial composition. This, too, is preclinical; evidence remains at the in vitro and animal level.
Importantly, Lactobacillus and Bifidobacterium strains previously shown to stimulate IL-12 and IFN-γ production in human PBMC were found to be relatively poor inducers of these cytokines in a comparative experiment. Instead, novel probiotic S. thermophilus and Leuconostoc strains were found to be extremely good inducers of these Th1-type cytokines. This work was conducted using human PBMC in vitro. In vivo, probiotics are not in direct contact with PBMC; instead, probiotics interact with the epithelial cells of the gut, and they may be taken up by macrophages, dendritic cells, or M-cells at Peyer's patches, which can lead to the activation of lymphocytes. The strength of this evidence is preliminary — it is in vitro human-cell work without a clinical trial.
In a study screening 67 lactic acid bacteria isolated from fermented food for antagonistic activity against Streptococcus mutans (the causative pathogen of dental caries), Leuconostoc mesenteroides MJM60376 showed the highest antagonistic activity. L. mesenteroides MJM60376 also showed oral probiotic characteristics including weak acid production, lysozyme tolerance, adhesion to oral epithelial cells, antibiotic susceptibility, and good coaggregation ability with S. mutans. Furthermore, biofilm formation of S. mutans was significantly reduced when cocultured with L. mesenteroides. Evidence is in vitro and preclinical; controlled human trials for dental caries prevention using Leuconostoc have not been identified.
L. mesenteroides LVBH107 survived at acid, bile salts, lysozyme, and hydrogen peroxide conditions, auto-aggregated and co-aggregated with P. gingivalis, exhibited strong hydrophobicity and electrostatic action, and strongly adhered to gingival epithelial and HT-29 cells, exhibiting oral tissue adherence and colonization abilities. These findings are in vitro; their translation to human clinical endpoints remains to be established.
In a cell-based study, Leuconostoc mesenteroides was isolated from traditional dairy products and its probiotic characteristics were determined. HT-29 colorectal cells were treated with conditioned medium of the designated bacteria and cell apoptosis was studied using DAPI staining, flow cytometry, DNA ladder assays, and real-time quantitative PCR. L. mesenteroides promoted apoptosis in the colon cancer cell line by upregulation of MAPK1, Bax, and caspase 3, and downregulation of AKT, NF-κB, Bcl-XL expressions and some key onco-microRNAs such as miRNA-21 and miRNA-200b significantly (p ≤ 0.03).
A further study found that in Caco-2 and HT-29 cells, live Leuconostoc mesenteroides treatment resulted in an increase in PD-L1 expression, and this treatment stimulated interferon-gamma (IFN-γ) production in Jurkat T-cells. The combination of IFN-γ and L. mesenteroides was used in colon cancer cell lines and a resulting remarkable increase of over tenfold in PD-L1 expression was obtained.
All anticancer evidence is in vitro (cell culture); no human clinical trials specifically investigating Leuconostoc as an anticancer agent have been identified. It is noteworthy that these characteristics are completely strain-dependent. Evidence in this area remains highly preliminary.
L. mesenteroides lysate was found to possess antibacterial properties against Staphylococcus aureus and Pseudomonas aeruginosa. In a keratinocyte cell model, the lysate demonstrated noteworthy wound closure after a 24-hour treatment, along with a significant reduction in interleukin-6 levels and oxidative stress index. Modulation of the cell cycle was evident by decreasing G0/G1 phases and increasing S and G2/M phases, and enhanced expression of wound healing marker genes and proteins CDH1 was observed. L. mesenteroides lysate was concluded to exhibit immune-modulating and antibacterial properties, offering potential alternatives to conventional treatments for various skin conditions. This evidence is from in vitro cell models and does not constitute clinical human evidence.
A 2025 study investigated the modulatory effects of the probiotic L. mesenteroides H40 in an ICR mouse model of cognitive disorders. Cognitive disorders were induced in mice by the addition of scopolamine (1 mg/kg/day). The researchers demonstrated that L. mesenteroides H40 exhibits neuroprotective effects through anti-inflammatory, synaptic plasticity regulation, and antioxidant effects. The probiotic was suggested as a potential prophylactic functional food for cognitive disorders. This is a preclinical animal study; no human trial data are available for this application.
A monocentric randomized crossover trial at the University of Freiburg investigated the impact of sauerkraut consumption on human gut microbiota. The study included two intervention phases, each of 4 weeks duration, during which each participant consumed 100 g of fresh or pasteurized sauerkraut daily. The health benefits of sauerkraut consumption have been studied in a limited body of research, mostly on in vitro models. Human clinical trials are still scarce. It is important to note that sauerkraut is a multi-bacterial fermented food and that benefits observed cannot be attributed exclusively to Leuconostoc.
Leuconostoc species are encountered in several distinct forms, depending on the context of use:
No standardized human clinical dosage for Leuconostoc as an isolated supplement has been established in the peer-reviewed literature reviewed. All CFU values cited above are from preclinical (animal) models only.
Although the Leuconostoc genus is "generally recognized as safe" (GRAS), a few clinical human infection cases by this microorganism have been reported in the literature, leading to their classification as opportunistic pathogens.
Leuconostoc spp. are gram-positive bacteria whose pathogenic potential has been demonstrated, especially in immunocompromised patients and in those with risk factors such as oncologic diseases. They can cause infections presenting as pneumonia, meningitis, endocarditis, or bacteremia, with bacteremia and endocarditis being the most frequent. A clinically notable feature is their intrinsic resistance to vancomycin, which makes penicillin and other beta-lactam antibiotics the first-line treatment options.
Species of Leuconostoc are uncommon opportunistic pathogens, which can be isolated in critically ill patients, immunocompromised hosts, and in nosocomial infections. They are mostly isolated in bacteremia associated with intravascular devices and with the use of total parenteral nutrition. Other infections due to Leuconostoc spp. described in the literature include meningitis, bloodstream infections, urinary tract infections, and peritonitis.
Leuconostoc spp. are intrinsically resistant to vancomycin. Often confused with other gram-positive species such as Streptococcus spp. and Enterococcus spp., and with innate resistance to glycopeptides, this etiology poses significant difficulties especially from a diagnostic point of view. Although rarely described in clinical practice, Leuconostoc infections are most certainly underdiagnosed given the difficulties posed by microbiological testing.
Leuconostoc bacteremia in a clinical context is most commonly seen in immunocompromised patients; cases have also been documented in previously healthy individuals following vancomycin therapy with prolonged ICU stays. Given that many empiric antimicrobial regimens used for immunocompromised patients contain vancomycin or teicoplanin, persistence of fever in such patients may indicate Leuconostoc infection. Leuconostoc pseudomesenteroides is facultatively anaerobic, catalase-negative, intrinsically resistant to glycopeptides, and is known to cause infections in immunocompromised patients, confirming its opportunistic and nosocomial potential.
Because they are an uncommon cause of disease in humans, standard commercial identification kits are often unable to identify the organism. This means that Leuconostoc infections may go undetected or be misidentified, particularly in clinical settings relying on automated identification systems.
Further research is required to investigate the specific mechanisms of action and health benefits of Leuconostoc-derived EPS in vivo. The health benefits of fermented foods containing Leuconostoc have been studied in a limited body of research, mostly on in vitro models; human clinical trials are still scarce. The totality of evidence for Leuconostoc as a targeted probiotic supplement in humans remains at an early, largely preclinical stage. Strain-specific effects are documented and results should not be generalized across species or strains.
Health conditions that Leuconostoc may help support.
Body systems that Leuconostoc may help support.
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