Streptococcus Thermophilus
Streptococcus thermophilus (Streptococcus salivarius subsp. thermophilus)
Also known as: S. thermophilus, yogurt starter culture, thermophilic streptococcus
This ingredient is classified as unclassified risk (GIRI score: 1.5/10).
Safety Profile
Known Safety Concerns
- Theoretical virulence gene transfer (extremely rare)
- Theoretical bacteremia in severely immunocompromised patients
- Shares genus with pathogenic streptococci -- species verification important
Contraindications
- Theoretical virulence gene transfer (extremely rare)
- Theoretical bacteremia in severely immunocompromised patients
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
Streptococcus thermophilus is a food-grade lactic acid bacterium used in yogurt and cheese production with GRAS status and extensive human consumption history. Produces lactase, beneficial in lactose intolerance.
Biological and Chemical Classification
- Scientific Name
- Streptococcus thermophilus (Streptococcus salivarius subsp. thermophilus)
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Executive Summary — Ingredient Assessment
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or RCT)
- Main clinical benefit observed: Probiotic
- Evidence consistency: High consistency across studies (100%)
- Theoretical virulence gene transfer (extremely rare)
- Theoretical bacteremia in severely immunocompromised patients
- Shares genus with pathogenic streptococci -- species verification important
The available scientific evidence for Streptococcus Thermophilus indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.
Total SETI Score
High risk| Evidence quality | 10/40 |
| Evidence consistency | 20/20 |
| Safety signals | 0/20 |
| Study recency | 10/10 |
| Evidence transparency | 10/10 |
Evidence Summary
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or systematic review)
- 0 studies identified benefits or no safety concern (GREEN)
- 10 studies reported limited or advisory safety evidence (YELLOW)
Evidence Policy
Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.
Last updated: 25 მარ 2026, 22:46
Evidence Distribution
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Observational / other LOW evidence YELLOWDiet-microbiome associations in 10,068 individuals from the Human Phenotype Project to guide personalized nutrition. ↗Segev T et al.. Diet-microbiome associations in 10,068 individuals from the Human Phenotype Project to guide personalized nutrition.. Nat Med. 2026. PMID:41872600.PMID 41872600 ↗Journal Nat MedYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41872600/
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Observational / other LOW evidence YELLOWSupragingival dental biofilm microbiomes of tobacco heating system smokers, cigarette smokers and non-smokers. ↗Bou017eac E et al.. Supragingival dental biofilm microbiomes of tobacco heating system smokers, cigarette smokers and non-smokers.. Clin Oral Investig. 2026. PMID:41870676.PMID 41870676 ↗Journal Clin Oral InvestigYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41870676/
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Observational / other LOW evidence YELLOWThe effects of dairy products containing Lactobacillus bulgaricus and Streptococcus thermophilus on bone turnover biomarkers and bone mineral density: a pilot trial… ↗Rueangsri N et al.. The effects of dairy products containing Lactobacillus bulgaricus and Streptococcus thermophilus on bone turnover biomarkers and bone mineral density: a pilot trial study.. Front Nutr. 2026. PMID:41867674.PMID 41867674 ↗Journal Front NutrYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41867674/
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Observational / other LOW evidence YELLOWRole of microbial interactions in the impaired cultivability of thermophilic lactic acid bacteria in natural whey starter for Parmigiano Reggiano PDO cheese… ↗Cristofolini M et al.. Role of microbial interactions in the impaired cultivability of thermophilic lactic acid bacteria in natural whey starter for Parmigiano Reggiano PDO cheese production.. Front Microbiol. 2026. PMID:41859451.PMID 41859451 ↗Journal Front MicrobiolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41859451/
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Observational / other LOW evidence YELLOWEffect of low-dose irradiation of starter culture on fermentation and physicochemical properties of set-type yogurt. ↗Danyo EK et al.. Effect of low-dose irradiation of starter culture on fermentation and physicochemical properties of set-type yogurt.. Int J Radiat Biol. 2026. PMID:41854434.PMID 41854434 ↗Journal Int J Radiat BiolYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41854434/
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Observational / other LOW evidence YELLOWPotential use of whey in kefir production: evaluation of fermentation kinetics and microbiota. ↗Biu00e7er Y et al.. Potential use of whey in kefir production: evaluation of fermentation kinetics and microbiota.. Food Sci Anim Resour. 2026. PMID:41849038.PMID 41849038 ↗Journal Food Sci Anim ResourYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41849038/
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Observational / other LOW evidence YELLOWYogurt application and postbiotic effects on mouse intestinal cells of Lacticaseibacillus paracasei HKWS110u00a0isolated from Prunus yedoensis. ↗Mijid N et al.. Yogurt application and postbiotic effects on mouse intestinal cells of Lacticaseibacillus paracasei HKWS110u00a0isolated from Prunus yedoensis.. Food Sci Anim Resour. 2026. PMID:41848934.PMID 41848934 ↗Journal Food Sci Anim ResourYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41848934/
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Observational / other LOW evidence YELLOWDeveloping Indigenous Plant-Enriched Yogurt to Enhance Iron Solubility-A Collaboration With Senegalese Women Farmers. ↗Ifeh C et al.. Developing Indigenous Plant-Enriched Yogurt to Enhance Iron Solubility-A Collaboration With Senegalese Women Farmers.. J Food Sci. 2026. PMID:41830445.PMID 41830445 ↗Journal J Food SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41830445/
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Observational / other LOW evidence YELLOWA Pressure Cook-Cool Process with Coconut Oil and Thai Herbs Enhances Resistant Starch, Antioxidant Activity, and Prebiotic Potential in Khao Dawk Mali… ↗Luang-In V et al.. A Pressure Cook-Cool Process with Coconut Oil and Thai Herbs Enhances Resistant Starch, Antioxidant Activity, and Prebiotic Potential in Khao Dawk Mali 105 (KDML 105).. Foods. 2026. PMID:41829107.PMID 41829107 ↗Journal FoodsYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41829107/
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Observational / other LOW evidence YELLOWGut Microbiota Signatures and Potential Mediators in the Trajectory of Age-related Macular Degeneration: A Phased Atlas by Genetic Inference. ↗Zhou Y et al.. Gut Microbiota Signatures and Potential Mediators in the Trajectory of Age-related Macular Degeneration: A Phased Atlas by Genetic Inference.. Int J Med Sci. 2026. PMID:41799763.PMID 41799763 ↗Journal Int J Med SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41799763/
Score Transparency
0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.
Method: Q = number of approved references ÷ 10 (capped at 1.0)
Limited — mostly case reports or animal studies
Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.
Mixed or neutral — roughly equal benefit and risk signals
Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.
One or more monitoring-level safety signals active
Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.
Final GIRI Score for Streptococcus Thermophilus. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
Full methodology & data sources
The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.
- References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
- Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
- Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
- Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Low classification for Streptococcus Thermophilus
A score of 1.5 places this ingredient in the Low band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
0 approved references.
Limited — mostly case reports or animal studies (Level 4–5).
Neutral or mixed — benefit and risk signals roughly balanced.
No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.
No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).
How are the Low / Moderate / High / Critical thresholds defined?
The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:
| Level | Score | Meaning |
|---|---|---|
| LOW | 0.0 – 2.9 | Sparse or predominantly beneficial evidence. No active safety alerts. |
| MODERATE | 3.0 – 5.4 | Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups. |
| HIGH | 5.5 – 7.4 | Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended. |
| CRITICAL | 7.5 – 10 | Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision. |
Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.