# Streptococcus thermophilus R27

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/streptococcus-thermophilus-r27
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-03
**Evidence Score:** 2 / 10
**Category:** Fermented/Probiotic
**Also Known As:** S. thermophilus R27, ST-R27, Streptococcus thermophilus strain R27, S. thermophilus R-27, Thermophilic streptococcus R27

## Overview

Streptococcus thermophilus R27 is a [probiotic](/ingredients/condition/gut-health) bacterial strain distinguished by its exceptional acid and bile resistance, enabling survival through harsh gastrointestinal conditions. Its primary mechanism involves adhesion to intestinal epithelial cells via surface-expressed proteins, facilitating colonization and competitive exclusion of pathogens.

## Health Benefits

• Gastrointestinal survival and tolerance - In vitro studies show survival at pH 2.0 for up to 60 minutes and bile tolerance up to 360 minutes (preliminary evidence)
• Intestinal adhesion properties - Demonstrates adhesion to HT-29 intestinal cells at 10^8 CFU/mL concentrations linked to 80.4% hydrophobicity (in vitro evidence only)
• Folate and bacteriocin production - Genomic analysis reveals capacity for vitamin B9 synthesis and antimicrobial compound production (preliminary evidence)
• [Antioxidant activity](/ingredients/condition/antioxidant) - Produces superoxide dismutase and NADH peroxidase enzymes (in vitro evidence only)
• Potential [immunomodulat](/ingredients/condition/immune-support)ion - Shows [anti-inflammatory](/ingredients/condition/inflammation) effects on U937 cell lines in preclinical studies (preliminary evidence)

## Mechanism of Action

S. thermophilus R27 expresses surface-layer proteins and mucus-binding proteins that mediate adhesion to intestinal epithelial HT-29 cells, achieving 80.4% hydrophobicity which correlates with colonization efficiency. The strain produces lactic acid via homofermentative [metabolism](/ingredients/condition/weight-management), lowering luminal pH and creating a hostile environment for pathogenic bacteria. Additionally, it may stimulate pattern recognition receptors such as TLR-2 on epithelial cells, modulating innate immune signaling through [NF-κB](/ingredients/condition/inflammation) pathway regulation.

## Clinical Summary

Current evidence for S. thermophilus R27 is primarily derived from in vitro studies rather than human clinical trials, limiting the strength of health claims. In vitro data demonstrate survival at pH 2.0 for up to 60 minutes and bile tolerance sustained for up to 360 minutes, suggesting functional gastrointestinal transit capability. Adhesion studies using HT-29 intestinal cell models at 10^8 CFU/mL concentrations document 80.4% cell surface hydrophobicity, a recognized proxy marker for colonization potential. No large-scale randomized controlled trials in human subjects have been published for this specific strain, and all functional conclusions remain preliminary.

## Nutritional Profile

Streptococcus thermophilus R27 is a lactic acid bacterium used primarily as a starter culture in fermented dairy products (yogurt, cheese) and as a probiotic adjunct, rather than consumed as a standalone nutritional source. Its nutritional relevance derives from its metabolic outputs during fermentation and its intrinsic bioactive properties:

**Bioactive Compounds Produced:**
• **Folate (Vitamin B9):** Genomic analysis confirms genes for de novo folate biosynthesis (folP, folC, folE, folK clusters). S. thermophilus strains in general can produce 20–200 µg/L folate in fermented milk; R27-specific quantification is pending but genomic capacity is confirmed.
• **Bacteriocins / Antimicrobial peptides:** Genomic evidence indicates bacteriocin-related gene clusters (thermophilin-like compounds), which may contribute to competitive exclusion of pathogens in the gut. Exact concentrations are strain- and media-dependent.
• **Exopolysaccharides (EPS):** S. thermophilus strains commonly produce EPS (50–800 mg/L in milk-based media), contributing to [prebiotic](/ingredients/condition/gut-health)-like activity, texture modification, and potential [immunomodulatory](/ingredients/condition/immune-support) effects. R27-specific EPS yield requires empirical confirmation.
• **Lactic acid:** Primary metabolic end-product; typically 6–12 g/L in fermented milk, contributing to pH reduction (pH ~4.2–4.6), improved mineral solubility and bioavailability (especially calcium and magnesium), and pathogen inhibition.

**Impact on Host Nutrient Bioavailability (in fermented dairy matrix):**
• **Lactose reduction:** S. thermophilus expresses β-galactosidase, hydrolyzing 20–40% of lactose during fermentation, improving tolerance in lactose-maldigesters.
• **Calcium & Magnesium:** Acidification of the dairy matrix increases soluble calcium and magnesium fractions by approximately 10–25%, enhancing intestinal absorption.
• **B-vitamins:** In addition to folate, minor contributions to riboflavin (B2) and niacin (B3) pools have been documented for S. thermophilus species (~50–150 µg/L riboflavin in fermented milk).
• **Bioactive peptides:** Proteinase activity releases casein-derived bioactive peptides (e.g., ACE-inhibitory, [antioxidant](/ingredients/condition/antioxidant) peptides) during milk fermentation, though R27-specific peptide profiles are not yet characterized.

**Intrinsic Cellular Composition (per ~10^10 CFU, approximate):**
• Protein: ~50–55% of dry cell weight (primarily intracellular enzymes, surface-layer proteins contributing to the 80.4% cell-surface hydrophobicity reported for R27)
• Nucleic acids: ~10–15% dry weight
• Lipids (membrane phospholipids): ~5–8% dry weight
• Peptidoglycan and teichoic acids: ~20–30% dry weight, which may act as microbe-associated molecular patterns (MAMPs) with immunostimulatory potential

**Bioavailability Notes:**
• Folate produced by S. thermophilus is predominantly in the reduced polyglutamate form (5-methyltetrahydrofolate), which has moderate-to-high bioavailability (~50–70% relative to synthetic folic acid) but requires intestinal deconjugation for full absorption.
• Probiotic viability is critical for in situ nutrient production; R27 demonstrates acid tolerance at pH 2.0 for 60 minutes and bile tolerance for 360 minutes, supporting transit survival and potential continued metabolic activity in the upper intestinal tract.
• The high cell-surface hydrophobicity (80.4%) and HT-29 adhesion capacity at 10^8 CFU/mL may prolong intestinal residence time, extending the window for nutrient production and host interaction.
• As a thermophilic organism (optimal growth 37–45°C), metabolic activity and nutrient output are maximized during fermentation and in body-temperature environments rather than during cold storage.

## Dosage & Preparation

No clinically studied dosages for S. thermophilus R27 have been established due to absence of human trials. In vitro studies used 10^8 cells/mL for adhesion assays and 10% (v/v) inocula for tolerance tests, but these are not validated human doses. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Streptococcus thermophilus strains broadly have a long history of safe use in fermented dairy products and are generally recognized as safe (GRAS) by regulatory bodies, though strain-specific safety data for R27 in clinical populations is limited. Immunocompromised individuals, including those on immunosuppressive therapy, should exercise caution with [probiotic](/ingredients/condition/gut-health) supplementation due to rare reports of bacteremia associated with lactic acid bacteria in vulnerable patients. No clinically documented drug interactions specific to S. thermophilus R27 have been established, though concurrent antibiotic use may reduce probiotic viability and efficacy. Pregnancy and lactation safety has not been specifically studied for the R27 strain; consultation with a healthcare provider is advised before use in these populations.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses specifically on Streptococcus thermophilus R27 were identified in available sources. Evidence is limited to in vitro studies, genomic analyses, and animal research on related S. thermophilus strains, with no PubMed PMIDs available for R27-specific human trials.

## Historical & Cultural Context

Streptococcus thermophilus R27 has no documented traditional medicine use in systems like Ayurveda or TCM. Its role is purely industrial and modern, primarily used in dairy fermentation alongside Lactobacillus delbrueckii subsp. bulgaricus for yogurt production since the 20th century.

## Synergistic Combinations

Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus, Bifidobacterium lactis, Inulin, Fructooligosaccharides

## Frequently Asked Questions

### Can Streptococcus thermophilus R27 survive stomach acid?

In vitro studies show that S. thermophilus R27 can survive exposure to pH 2.0 conditions for up to 60 minutes, simulating the acidic environment of the human stomach. This acid tolerance is considered a critical prerequisite for a probiotic strain to reach the intestine in viable numbers, though in vivo confirmation in human subjects has not yet been published.

### How does Streptococcus thermophilus R27 adhere to the gut?

S. thermophilus R27 adheres to intestinal epithelial HT-29 cells through surface-expressed proteins and demonstrates 80.4% cell surface hydrophobicity at a concentration of 10^8 CFU/mL. High surface hydrophobicity is a recognized biochemical marker that correlates with a bacterium's ability to attach to mucosal surfaces, which is essential for probiotic colonization and competitive exclusion of harmful microorganisms.

### What is the difference between Streptococcus thermophilus R27 and other probiotic strains?

S. thermophilus R27 is distinguished by its combined acid resistance, extended bile tolerance of up to 360 minutes, and high intestinal cell adhesion capacity, which together suggest strong gastrointestinal survivability compared to some common probiotic strains. Unlike well-studied strains such as Lactobacillus rhamnosus GG, R27 lacks extensive human clinical trial data, so its comparative efficacy for specific health outcomes has not been rigorously established.

### What dose of Streptococcus thermophilus R27 is used in studies?

Adhesion and survival studies for S. thermophilus R27 have been conducted at concentrations of 10^8 CFU/mL in in vitro cell models, which represents a standard experimental concentration used to evaluate probiotic properties. A clinically validated dosing recommendation for human supplementation has not yet been established, as published evidence for this specific strain remains limited to laboratory research.

### Is Streptococcus thermophilus R27 safe for daily use?

The broader Streptococcus thermophilus species has a well-established safety record as a component of yogurt and fermented dairy, carrying GRAS status, but strain-specific safety trials for R27 in human populations have not been published. Daily use is likely low-risk for healthy adults, but individuals who are immunocompromised, pregnant, or taking antibiotics should consult a healthcare provider before supplementing with any probiotic, including S. thermophilus R27.

### Does Streptococcus thermophilus R27 produce folate naturally?

Genomic analysis of Streptococcus thermophilus R27 indicates the presence of folate biosynthesis genes, suggesting the strain may produce folate as a metabolic byproduct. However, clinical evidence on actual folate production levels and bioavailability in the human gut is currently limited. Further in vivo studies are needed to confirm whether supplementation with this strain meaningfully contributes to folate status.

### What antimicrobial compounds does Streptococcus thermophilus R27 produce?

Genomic analysis reveals that Streptococcus thermophilus R27 carries genes for bacteriocin production, which are antimicrobial peptides that may inhibit harmful bacteria in the gut. The specific bacteriocins produced and their effectiveness against pathogenic organisms remain largely unexplored in published clinical research. Preliminary evidence is restricted to genomic findings rather than functional studies demonstrating antimicrobial activity in the human gastrointestinal tract.

### Is Streptococcus thermophilus R27 suitable for individuals with lactose intolerance?

Streptococcus thermophilus R27 is a lactic acid bacterium commonly used in yogurt fermentation and may help digest lactose through its β-galactosidase enzyme activity. Many individuals with lactose intolerance tolerate fermented dairy products containing this strain better than unfermented milk. However, tolerance varies by individual, and those with severe dairy allergies should consult a healthcare provider before use.

---

*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
*License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*