Lactobacillus delbrueckii
1. Identity, Nomenclature, and Classification
Lactobacillus delbrueckii is a species of bacteria in the family Lactobacillaceae. The species carries the name of Max Delbrück, who lent his name to the Berlin Institute for the Fermentation Industries, where L. delbrueckii and L. delbrueckii subsp. bulgaricus were produced on an industrial scale from about 1896. A paper published in 1983 by Weiss, Schillinger, and Kandler described the high degree of shared identity between L. delbrueckii's subspecies, which had previously been considered separate species.
Within the NCBI taxonomy, the organism is classified as: cellular organisms → Bacteria → Bacillati → Bacillota → Bacilli → Lactobacillales → Lactobacillaceae → Lactobacillus. The L. delbrueckii group contains mainly obligate homofermentative bacteria, and the G+C content of most of the species is less than 40 mol%.
1.1 Subspecies
There are four subspecies differentiated by their metabolites and internal genetics. Lactobacillus delbrueckii is a rod-shaped, Gram-positive, non-motile bacterium with the common ability to ferment sugar substrates into lactic acid products under anaerobic conditions. The four recognized subspecies are:
- L. delbrueckii subsp. bulgaricus — First identified in 1905 by the Bulgarian doctor Stamen Grigorov, who isolated what was later termed Lactobacillus bulgaricus from a Bulgarian yogurt sample; the bacterium can be found naturally in the gastrointestinal tract of mammals living in the Sofia region and along the Balkan Mountain (Stara Planina) mesoregion of the Balkan peninsula. One strain, Lactobacillus bulgaricus GLB44, is extracted from the leaves of Galanthus nivalis (snowdrop flower) in Bulgaria.
- L. delbrueckii subsp. lactis — Designated Lactobacillus delbrueckii subsp. lactis (Orla-Jensen 1919) Weiss et al. 1984.
- L. delbrueckii subsp. delbrueckii — Differs from the dairy-associated subspecies in that it resides primarily in vegetable sources rather than dairy products.
- L. delbrueckii subsp. indicus — The most recent accepted subspecies, isolated from an Indian dairy.
1.2 Common Names and Synonyms
The subspecies bulgaricus is widely known colloquially as Lactobacillus bulgaricus. In bacterial taxonomy, the basionym for L. d. bulgaricus was "Thermobacterium bulgaricum" Orla-Jensen 1919. The entity became Lactobacillus bulgaricus in 1973 with the work of Rugosa and Hansen, and was reclassified as a subspecies under Lactobacillus delbrueckii in 1984. Historically, L. delbrueckii was also grouped under the designation "Thermobacterium" by early microbiologists.
1.3 Natural Sources and Habitats
As a species, L. delbrueckii is generally found in dairy products such as yogurt, milk, and cheese, with the exception of L. delbrueckii subsp. delbrueckii, which resides in vegetable sources. The species is also part of the microbiota of the lower reproductive tract of women.
L. delbrueckii subsp. bulgaricus was identified as the predominant bacterial strain in certain types of naturally fermented products in China and Mongolia. A collection of 298 L. delbrueckii strains from naturally fermented products in Mongolia, Russia, and West China was analyzed by multi-locus sequence typing based on eight conserved genes.
2. Traditional and Historical Use
Naturally fermented dairy products have a long history in China, Mongolia, and Russia. A book titled A New Account of Tales of the World (Shi Shuo Xin Yu) was published in the Eastern Jin Dynasty in China (AD 317–420), documenting the production of a fermented dairy product named "lao." Nomadic people across large rural areas of these countries still use traditional methods to produce fermented dairy products.
The interaction between L. bulgaricus and S. thermophilus directly affects the quality of fermented milk. Thousands of years ago, humans began to use fermentation to sour milk. The bacterial cultures underlying these traditions were transmitted over generations without any scientific understanding of their microbial nature.
Today, Lactobacillus delbrueckii subsp. bulgaricus is commonly used alongside Streptococcus thermophilus as a starter for making yogurt. The two species work in synergy, with L. d. bulgaricus producing amino acids from milk proteins, which are then used by S. thermophilus.
Lactobacillus delbrueckii, which taxonomically belongs to the genus Lactobacillus, has a lengthy history in the fermented milk industry. Beyond yogurt, Lactobacillus delbrueckii has also been identified as the core functional microorganism significantly contributing to flavor compound synthesis during the traditional production of Chinese Huizhou Mao-tofu.
3. Genomic Character and Evolutionary Biology
Both L. delbrueckii subsp. lactis and subsp. bulgaricus show the signs of reductive evolution through the elimination of superfluous genes, thereby limiting their carbohydrate metabolic capacities and amino acid biosynthesis potential. Genomic analysis indicates the adaptation of L. bulgaricus from a plant-associated habitat to the stable protein- and lactose-rich milk environment through the loss of superfluous functions and protocooperation with Streptococcus thermophilus.
One of the most important traits — lactose fermentation — in one of the economically most important dairy bacteria, L. delbrueckii subsp. bulgaricus, relies on horizontally acquired rather than deep ancestral genes. In this sense, this bacterium may be regarded as a natural GMO avant la lettre.
The subsp. lactis retained more extended carbohydrate metabolizing capabilities than subsp. bulgaricus but, due to high intra-subspecies diversity, very few carbohydrate substrates, if any, allow a reliable distinction of the two subspecies.
4. Key Constituents and Active Compounds
The metabolic activities of L. delbrueckii — such as efficient lactose utilization, rapid acidification, and high proteolytic activity — make it an indispensable starter culture in the dairy industry. Beyond its technological advantages, L. delbrueckii contributes significantly to human health through the production of bioactive peptides (BAPs), extracellular polysaccharides (EPS), and other functional metabolites with antioxidant, anti-inflammatory, and immunomodulatory effects.
4.1 Exopolysaccharides (EPS)
In dairy matrices, the major bioactive outputs most frequently reported for L. delbrueckii include proteolysis-derived bioactive peptides (BAPs) and exopolysaccharides (EPS), alongside other antimicrobial factors (e.g., organic acids and, in some strains, bacteriocin-like compounds).
EPS from Lactobacillus delbrueckii strains can enhance humoral immunity mediated by immunoglobulins produced by bone marrow lymphocytes (B lymphocytes). The B lymphocytes are responsible for specific recognition and removal of antigens that are extracellularly located. EPS from LAB can also enhance cell-mediated immune responses such as natural killer cell tumoricidal activity, T-lymphocyte proliferation, and mononuclear cell phagocytic capacity.
The OLL1073R-1 strain was selected specifically for its ability to produce large amounts of immunomodulatory exopolysaccharide (EPS). OLL1073R-1 and its derived EPS (R-1 EPS) can augment NK cell activity, and R-1 EPS shows anti-influenza virus effects both in vitro and in vivo.
4.2 Bioactive Peptides (BAPs)
Probiotic L. delbrueckii strains are mainly isolated from dairy products, supporting the prediction of core genome enzymes related to a conserved proteolytic and metabolic sugar system. This high metabolic property enhances the fermentation ability of these strains with the production of essential metabolites (e.g., bioactive peptides, lactate, short-chain fatty acids, and vitamins).
The synthesis of these compounds requires specific enzymes (e.g., proteinases and peptidases, glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, phosphoketolase, acetate kinase, lactate dehydrogenase, riboflavin kinase, and thiamine pyrophosphokinase), which are involved in proteolysis and both phosphoketolase and Embden–Meyerhof (EMP) metabolic pathways.
4.3 Beta-Galactosidase (Lactase)
Lactobacillus delbrueckii, particularly subsp. bulgaricus, produces the enzyme beta-galactosidase (lactase), which is the key mechanism enabling lactose digestion and supporting individuals with lactose intolerance. When present in fermented dairy products such as yogurt, L. delbrueckii helps break down lactose into glucose and galactose, which are more readily absorbed in the human gut.
4.4 Antimicrobial Compounds
A vital feature derived from the fermentation process by probiotic strains is their antimicrobial activity due to organic acids, hydrogen peroxide, and bacteriocins production. Seven tested L. delbrueckii subsp. bulgaricus (GLB) strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity, and some neutralized, catalase- and heat-treated cell-free supernatants inhibited more than 83% of the test strains. This bacteriocin-like inhibitory substance production can render them valuable probiotics in the control of H. pylori infection.
4.5 Antioxidant Components
Many beneficial effects are elicited by components of the bacteria cell membrane or secreted molecules, such as cell surface proteins, exopolysaccharides, bioactive metabolites, and peptides. EPS from L. delbrueckii subsp. bulgaricus has been shown in preclinical cell models to activate the Keap1/Nrf2 antioxidant pathway. The Keap1/Nrf2 pathway is activated in response to oxidative stress, and Keap1 undergoes conformational changes, leading to the stabilization and nuclear translocation of Nrf2. Subsequently, Nrf2 binds to antioxidant response elements (AREs) in the promoter regions of its target genes, promoting their transcription and expression.
5. Mechanisms of Action
L. delbrueckii is recognized for its health-promoting effects, including immune modulation, anti-inflammatory activity, and enhanced lactose digestion through the secretion of bioactive peptides and extracellular polysaccharides.
Mechanisms underlying the protective effects of L. delbrueckii include the enhancement of the intestinal barrier function, the secretion of antimicrobial compounds, and the modulation of intestinal epithelial and mucosal immune cell responses. Several probiotics, including L. delbrueckii, have been reported to exert anti-inflammatory effects by the modulation of innate and adaptive immune responses — specifically, modulating the balance between Th1, Th2, Th17, and Treg cells, down-regulating the production of pro-inflammatory cytokines, and stimulating anti-inflammatory cytokine production.
L. delbrueckii can tolerate industrial and gastrointestinal stressors, and this property could be enhanced by incorporating these microorganisms into dairy matrices. The biotherapeutic activity of L. delbrueckii has been extensively demonstrated in intestinal inflammation, enteric infections, and metabolic and psychological disorders.
6. Scientific Evidence by Area of Use
6.1 Lactose Intolerance
Evidence strength: Moderate; best-supported application.
Lactobacillus delbrueckii subsp. bulgaricus is a non-pathogenic microorganism that produces lactic acid and has the ability to change the intestinal milieu, reduce lactose intolerance, and improve the immune system. Clinical and population-level observations suggest that consumption of yogurt/fermented milk containing L. delbrueckii (often in combination with other starter cultures) may reduce common lactose intolerance–related symptoms such as bloating, abdominal discomfort, and diarrhea, thereby improving overall tolerance to dairy intake. Its rapid acidification and lactic acid production not only ensure fermentation efficiency but also enhance the digestibility of dairy products for individuals with lactose intolerance.
Several clinical studies have shown that individuals with lactose intolerance tolerate yogurt containing live cultures, including L. delbrueckii, better than unfermented milk. The underlying mechanism is the delivery of microbial lactase (beta-galactosidase) to the intestinal lumen, where it acts during digestion, a mechanism that has been extensively characterized. However, much of the human evidence comes from studies of yogurt as a whole food — containing both L. delbrueckii and S. thermophilus — making strain-specific attribution difficult.
6.2 Immune System Modulation and Respiratory Infection Prevention
Evidence strength: Moderate; multiple human RCTs for specific strain OLL1073R-1.
A meta-analysis of two independent clinical studies examined whether intake of yogurt fermented with Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 had an effect on resistance to the common cold. In the two studies, fifty-seven (median age 74.5 years) and eighty-five healthy elderly individuals (median age 67.7 years) were participants; subjects were instructed to eat 90 g yogurt or drink 100 ml milk once per day over an 8- or 12-week period. The meta-analysis showed the risk of catching the common cold was about 2.6 times lower (OR 0.39; P = 0.019) in the yogurt group than in the milk group, and the increase of natural killer cell activity was significantly higher in the yogurt group.
A further study suggests that continuous daily ingestion of OLL1073R-1 yogurt may help prevent infection with influenza A virus subtype H3N2 in elderly subjects with weakened immunity, by increasing the production of influenza A virus subtype H3N2-bound salivary IgA.
A clinical study showed that the daily consumption of yogurt fermented with OLL1073R-1 augmented serum antibody titers against a seasonal influenza vaccine. In the first trial, the geometric mean titers (GMTs) of the H3N2 and B viruses were significantly higher in the yogurt group than in the placebo group. Furthermore, the cumulative days of ill health, such as throat complaints, upper respiratory inflammation, and cold, were significantly lower in the yogurt group than in the placebo group. Therefore, daily intake of yogurt fermented with L. bulgaricus OLL1073R-1 could reduce the duration of symptoms caused by respiratory infections and act as a mucosal adjuvant enhancing acquired immune responses against vaccines.
A more recent randomized controlled trial examined immune function. The effect of OLL1073R-1- and OLS3059-fermented yogurt on immune function was evaluated. Intake of the yogurt enhanced the activity of conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs), as well as CD4+ T cell activity and salivary secretory IgA production.
Important caveat: most studies in this area come from Japanese research groups using the specific OLL1073R-1 strain, and many involve yogurt as the delivery vehicle rather than isolated bacterial supplement forms. The findings are therefore strain-specific and cannot be extrapolated to L. delbrueckii as a whole species.
6.3 Anti-Fatigue Effects
Evidence strength: Preliminary; single RCT.
A randomized, double-blinded, placebo-controlled trial investigated whether ingesting OLL1073R-1 yogurt could ameliorate summer heat fatigue in 49 healthy males (median age 40.0 ± 6.0 years; 30–49 years) who felt fatigued every summer. Fatigue was evaluated by visual analogue scales (VAS) and the balance of sympathetic/parasympathetic nervous systems. After 12 weeks of ingestion in early autumn, the VAS fatigue scores in the yogurt group were lower than those of the placebo group. These results indicate that yogurt fermented with L. bulgaricus OLL1073R-1 can ameliorate summer heat fatigue lasting up to early autumn. This is a single, small trial and requires replication.
6.4 Gut Microbiota, Inflammation, and Immune Parameters
Evidence strength: Emerging; one recent placebo-controlled human RCT.
A randomized, double-blind, placebo-controlled clinical trial in healthy adults assessed the strain L. delbrueckii subsp. bulgaricus LB42's effects on gut microbiota, inflammatory markers, and immune parameters including LL-37, calprotectin, immunoglobulins, and immune cell subsets. The clinical trial revealed improved gastrointestinal function, sleep quality, and reduced fecal calprotectin. LB42 enhanced IgA/IgG responses and reshaped gut microbiota by enriching short-chain fatty acid producers and reducing inflammation. Genomic screening confirmed the absence of pathogenic, resistance, or virulence genes. LB42 exhibited no cytotoxicity or hemolysis, showed broad antibiotic sensitivity, and adhered strongly to Caco-2 cells. Acute oral toxicity testing revealed no adverse effects in mice. In humans, LB42 was well tolerated without biochemical or hematological abnormalities, and no adverse events or allergic reactions were reported.
6.5 Inflammatory Bowel Disease (IBD)
Evidence strength: Preclinical (animal models); limited direct human evidence.
A study showed that orally administered dairy lactobacilli can not only modulate mucosal but also systemic immune responses and constitute an effective treatment of IBD. However, this conclusion derives primarily from animal models. Inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn's disease, are characterized by spontaneous and chronic inflammation of the gastrointestinal tract. The administration of probiotics may balance the indigenous microbiota, and several have been proposed for IBD treatment, showing a protective effect in animal models of experimental colitis and, for some, also in human clinical trials. The specific evidence for L. delbrueckii in IBD in humans remains limited and requires further RCTs.
6.6 Helicobacter pylori Eradication
Evidence strength: Mixed; one positive prospective RCT and one negative pilot study.
A prospective randomized controlled clinical trial evaluated the effect of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus on Helicobacter pylori eradication in different periods of therapeutic protocol. Infected patients were randomized to one-week tailored triple therapy (esomeprazole 20 mg bid, clarithromycin 500 mg bid/metronidazole 400 mg tid if clarithromycin resistant, and amoxicillin 1000 mg bid) with placebo (group 1, n=100); one week of pretreatment with probiotics (group 2, n=100); and one week of pretreatment with probiotic followed by one week of the same probiotics after treatment (group 3, n=100). PP analysis involved 292 patients. Successful eradication was observed in 229 patients; by PP analysis, the eradication rates were significantly higher (P<0.01, 95% CI; 0.71–0.97) in groups 2 and 3 than in group 1.
However, a separate pilot study produced a negative result. A pilot study used a 3-gram sachet (3 billion cells) of L. delbrueckii GLB44 plus 22.3 mg of esomeprazole b.i.d. for 14 days in healthy H. pylori-infected volunteers. Nine subjects were entered, and because all failed to achieve a negative urea breath test, the stopping rule required the study to end. The authors were unable to confirm reports of achieving a high H. pylori cure rate with L. delbrueckii GLB44 plus a PPI. These conflicting results mean evidence in this area is currently inconclusive.
6.7 Blood Lipid Profiles and Body Weight
Evidence strength: Preliminary; one small randomized pilot trial.
A pilot trial aimed to evaluate the efficacy of Lactobacillus delbrueckii subsp. bulgaricus in improving body weight, obesity-related outcomes, and lipid profiles of overweight people. Thirty-six overweight participants were randomly assigned to either a probiotic or a placebo group. A placebo powder or L. bulgaricus powder containing 1 × 108 colony-forming units (CFU) of the probiotic was administered daily for 12 weeks. L. bulgaricus supplementation under the present condition did not affect the body weight, fat percentage, or body mass index (BMI) of the participants, while it resulted in a notable decrease in blood triglyceride (TG) levels, which corresponded to a lowering of the TG proportion in the composition of large VLDL (L–XXL sized fractions) and HDL (M and L fractions) in the probiotic-treated group. This is a small, underpowered pilot study, and findings require replication in larger trials.
6.8 Antioxidant Activity
Evidence strength: Preclinical (animal and in vitro); limited human data.
A PubMed-indexed study showed that the level of thiobarbituric acid-reactive substances was lower in low-density lipoproteins from rats fed on oxidized oil with freeze-dried powder of the 2038 culture than without it. The level of vitamin E in plasma was higher in the rats fed on the oxidized oil with the freeze-dried powder than without it. This is animal data. In vitro research using cell models has shown that several studies have indicated that EPS can activate the Keap1/Nrf2 pathway, thereby increasing the expression of antioxidant genes and enhancing antioxidant enzyme activity.
6.9 Potential Anti-Cancer Activity
Evidence strength: Preclinical only; animal model data.
L. delbrueckii's role in gut health, cholesterol reduction, and potential anti-cancer activity has been highlighted in recent studies, underscoring its value as a probiotic. EPS from LAB are considered good candidates for immunotherapeutic agents against cancer because they usually have low side effects and are less cytotoxic. In animal research, in a murine colitis-associated cancer model, 1 × 109 CFU of L. delbrueckii subsp. bulgaricus were diluted in 200 µL of PBS and given orally to each mouse 3 times a week during the entire experimental period. Prior to tumor induction, mice were randomly distributed in 2 groups (n=10). No comparable human clinical trial data are available; all anti-cancer evidence for L. delbrueckii currently remains in the preclinical stage.
6.10 Antiviral Activity (Coronavirus)
Evidence strength: Preliminary in vitro; no human trial data.
Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 is used as a starter in yogurt and produces exopolysaccharides (R-1 EPS) with immunomodulatory effects. Several clinical studies suggest a potential inhibitory effect of yogurt fermented with OLL1073R-1 against infections. The effects include reducing the risk of catching the common cold, enhancing dendritic cell and natural killer (NK) cell activities, and augmenting antibody production in serum and saliva. Regarding potential coronavirus effects, cell culture supernatant was obtained by stimulating human peripheral blood mononuclear cells with R-1 EPS (R-1 sup), and the inhibitory effect of R-1 sup on coronaviruses was evaluated using the human lung cell line MRC5. High levels of proinflammatory cytokines were detected in R-1 sup, and replication of both HCoV-229E and SARS-CoV-2 was significantly suppressed in MRC5 cells pretreated with R-1 sup. This is in vitro research only; no human trials have been conducted.
7. Body Systems and Health Areas of Association
- Gastrointestinal System: Lactose digestion; gut microbiota modulation; reduced fecal calprotectin; potential benefit in IBD (primarily preclinical).
- Immune System: NK cell activation; IgA, IgG, and IgM augmentation; dendritic cell activation; Th1/Th2/Treg cell balance modulation.
- Respiratory System: Reduced incidence of common cold and influenza in elderly populations (OLL1073R-1 strain-specific evidence).
- Cardiovascular / Metabolic: Triglyceride reduction (pilot data only); preclinical evidence of cholesterol metabolism effects.
- Antioxidant Defense: Keap1/Nrf2 pathway activation (in vitro); antioxidant enzyme enhancement in animal models.
- Female Reproductive Tract: L. delbrueckii is part of the microbiota of the lower reproductive tract of women.
8. Dosage Forms and Dosages Reported in Studies
L. delbrueckii is available as a dietary supplement in various strengths and dosage forms. Some dietary supplements that contain L. delbrueckii also contain many other ingredients, including other probiotics.
The probiotic composition can take the final form of either liquid, solid, or semi-solid. For example, the probiotic composition may be a set or creamy cultured beverage (or smoothie). The probiotic composition may also be lyophilized and separated into specific dosing units. The dosing units may be packaged in one of several forms including but not limited to packets, capsules, tablets, or caplets.
Dosages reported in peer-reviewed clinical studies include:
- 90 g of OLL1073R-1 yogurt once per day over 8 or 12 weeks (elderly cold-prevention trials).
- 1 × 108 CFU of L. bulgaricus powder daily for 12 weeks (overweight adults, lipid-profile trial).
- A 3-gram sachet (3 billion cells) of L. delbrueckii GLB44 plus esomeprazole b.i.d. for 14 days (H. pylori pilot study).
- 1 × 109 CFU diluted in 200 µL of PBS given orally to mice 3 times per week (murine colitis-associated cancer model).
- Solid dosage form compositions for lactose intolerance have been described as containing between 100 million and 10 billion colony-forming units of Lactobacillus delbrueckii subsp. bulgaricus.
No universally established human therapeutic dosage for L. delbrueckii as a standalone probiotic supplement has been defined by any regulatory body or pharmacopeia. Dosages vary considerably between studies and between strains.
9. Safety Considerations and Interactions
9.1 General Safety Profile
L. delbrueckii has a safety level supporting its use as a probiotic and in the food industry. Although commercial probiotic strains have a qualified presumption of safety (QPS) or are generally recognized as safe (GRAS status), it is essential to evaluate candidate probiotics for characteristics related to both their safety for consumption and their biotechnological application. Lactobacillus delbrueckii is widely used in the food industry, and scientific evidence supports its role as a potential probiotic in a strain-specific manner.
Few plasmids have been identified in L. delbrueckii, reducing the spread of antibiotic-resistance genes. Additionally, this species has a lower capacity to act as a pathogen.
9.2 Antibiotic Resistance
Lactobacillus delbrueckii species is mainly intrinsically antibiotic-resistant. This is an important safety consideration in the context of probiotic use, particularly regarding the potential for transfer of resistance genes to pathogenic bacteria. However, the absence of acquired or mobile resistance genes is a favorable safety feature. L. delbrueckii subsp. bulgaricus LB42 underwent genomic screening confirming the absence of pathogenic, resistance, or virulence genes. LB42 exhibited no cytotoxicity or hemolysis and showed broad antibiotic sensitivity.
9.3 Adverse Effects Reported in Clinical Trials
Common side effects include gas and an upset stomach. Serious side effects are rare but include infections in some people who are at high risk for infections. In the LB42 clinical trial in humans, the strain was well tolerated without biochemical or hematological abnormalities, and no adverse events or allergic reactions were reported.
9.4 Gastrointestinal Tolerance
Survival and growth of L. delbrueckii strains under harsh gastrointestinal conditions is essential for their probiotic potential. Their tolerance to acids and bile salts can be assessed by exposing isolated strains to low pH values and concentrations of bile salts. L. delbrueckii can tolerate industrial and gastrointestinal stressors, and this property could be enhanced by incorporating these microorganisms into dairy matrices.
9.5 Regulatory Standing
The species holds GRAS (Generally Recognized as Safe) status in the United States for food applications, particularly in yogurt production. The European Food Safety Authority (EFSA) has evaluated multi-strain probiotic preparations including Lactobacillus delbrueckii subsp. lactis and subsp. bulgaricus, delivering opinions on their safety for target species, consumers, users, and the environment. Such assessments have focused on veterinary/feed applications, and separate EFSA opinions address human food applications through the qualified presumption of safety (QPS) framework applicable to lactic acid bacteria in fermented foods.
References
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