Probiotics Testing Services: Viability, Identity, Purity & Potency Assurance

As an independent third-party testing service provider, we offer comprehensive analytical services for probiotic products – including dietary supplements, functional foods, infant formula, dairy products (yogurt, kefir), fermented beverages, and pharmaceutical formulations containing live beneficial bacteria or yeasts. Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”. Accurate testing is critical to verify strain identity, viable count (colony‑forming units – CFU), absence of contaminants, and stability throughout shelf‑life. Our accredited laboratory follows international standards (ISO 19344, ISO 17604, IDF standards, USP <2021>, AOAC, China GB 4789.35) to deliver reliable, reproducible, and regulatory‑ready results. This article outlines our probiotic testing capabilities – including scope, key test items, and standard test methods – to help manufacturers, quality assurance teams, and regulatory bodies ensure product efficacy and compliance.

1. Our Testing Scope for Probiotic Products

We cover a wide range of probiotic strains, product formats, and testing objectives:

By probiotic microorganism: Lactobacillus species (L. acidophilus, L. rhamnosus, L. casei, L. plantarum, L. reuteri, L. paracasei, etc.); Bifidobacterium species (B. bifidum, B. longum, B. breve, B. animalis subsp. lactis, etc.); Streptococcus thermophilus; Bacillus species (B. coagulans, B. subtilis, B. clausii); Saccharomyces boulardii (yeast); Pediococcus, Enterococcus, and other emerging probiotic strains.

By product matrix: Powder (stick packs, bulk, capsules); Tablets and caplets; Capsules (gelatin or vegetable); Liquids (drops, suspensions, fermented milk); Gummies; Fermented foods (yogurt, kefir, kimchi, sauerkraut); Infant formula; Pet probiotics; Pharmaceutical grade preparations.

By test parameter: Viable count (CFU/g, CFU/mL, or CFU per serving); Strain identification (genetic or biochemical); Purity (absence of non‑probiotic contaminants); Stability (accelerated and real‑time); Antimicrobial susceptibility (when required); Label claim verification.

By industry standard / regulation: ISO 19344 (Milk and milk products – enumeration of lactic acid bacteria – flow cytometry method); ISO 17604 (Microbiology of the food chain – enumeration of microorganisms); USP <2021> (Microbiological examination of probiotic products); AOAC Official Methods (e.g., 2015.11 for enumeration of lactic acid bacteria); China GB 4789.35 (Food safety – microbiological examination of lactic acid bacteria in food); IDF standards series.

2. Key Test Items & Measurements We Perform

Our probiotic testing services are grouped into viability, identity, purity, and stability domains. All tests are performed under strict anaerobic conditions (for strict anaerobes) or microaerophilic conditions where required.

2.1 Viable Plate Count (Enumeration of Live Probiotics)

Total Viable Count of specific probiotic strains – using selective and/or differential media (e.g., MRS agar for Lactobacillus spp., Bifidobacterium selective agar – BSM, M17 agar for Streptococcus thermophilus, Sabouraud agar for Saccharomyces boulardii). Incubation under appropriate atmospheric conditions (anaerobic, microaerophilic, or aerobic). Results in colony‑forming units per gram (CFU/g) or per serving.
Mixed culture differentiation – for multi‑strain products, we use chromogenic media or colony morphology + biochemical confirmation to enumerate individual strains (when possible).
Method suitability (neutralisation) – validation to overcome inhibitory matrix components (e.g., oils, acids, preservatives) ensuring full recovery.
Results reporting – CFU count at time of analysis, with statistical uncertainty (log difference).

2.2 Strain Identity Confirmation

Biochemical identification – API 50 CHL, VITEK 2, or MALDI‑TOF MS (matrix‑assisted laser desorption/ionisation time‑of‑flight mass spectrometry) for genus and species confirmation.
Molecular identification – 16S rDNA sequencing (for bacteria) or ITS sequencing (for yeast); strain‑level identification by rep‑PCR (repetitive element PCR) or RAPD (random amplification of polymorphic DNA).
Strain‑specific PCR – detection of strain‑specific genetic markers (when known sequence provided).
Whole genome sequencing (WGS) – definitive strain characterisation and safety assessment (by arrangement).

2.3 Purity & Contaminant Testing

Absence of non‑probiotic bacteria (product purity) – by plating on non‑selective media (e.g., PCA) and identification of any colonies not matching expected probiotic morphology.
Absence of specified pathogens – Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7, coagulase‑positive staphylococci (per regional requirements).
Absence of bile‑tolerant Gram‑negative bacteria – for pharmaceutical‑grade probiotics (USP <2021>).
Yeast and mould contamination (non‑Saccharomyces).

2.4 Stability & Shelf‑Life Testing

Real‑time stability – viability monitoring at defined intervals (e.g., 0, 3, 6, 12, 18, 24 months) under recommended storage conditions (room temperature, refrigerated, frozen).
Accelerated stability – elevated temperature (e.g., 25°C, 30°C, 37°C) and/or humidity to predict shelf‑life.
In‑process stability – viability during manufacturing (mixing, compression, encapsulation, drying).
Moisture content and water activity (a_w) – correlations with viability loss.

2.5 Antimicrobial Susceptibility (Resistance) Testing

Minimum inhibitory concentration (MIC) – for antibiotic resistance profiling as per EFSA / FDA guidance (e.g., ampicillin, chloramphenicol, tetracycline, erythromycin, gentamicin).
Disc diffusion (Kirby‑Bauer) – screening for resistance markers (optional).

2.6 Activity & Functionality (Optional)

Bile salt hydrolase activity – semi‑quantitative assay (precipitation on BSH agar).
Acid tolerance test (simulated gastric juice) – viability after exposure to pH 2.0‑3.0 for specified time.
Autoaggregation / hydrophobicity – indicators of adhesion potential.

3. Standard Test Methods We Apply

All tests are performed according to internationally recognised standards. Our laboratory is ISO/IEC 17025 accredited and equipped with anaerobic chambers, microbiological safety cabinets, PCR systems, MALDI‑TOF MS, and automated enumeration systems.

3.1 Viable Count Standards

ISO 19344 (IDF 232) – Milk products – enumeration of lactic acid bacteria by flow cytometry (rapid method).
ISO 17604 (general enumeration of microorganisms in food chain).
USP <2021> (Microbiological examination of probiotic products – viable count, strain enumeration).
AOAC 2015.11 (enumeration of lactic acid bacteria in dietary supplements).
China GB 4789.35 (Lactic acid bacteria in food).
IDF 169 (enumeration of bifidobacteria).

3.2 Identity & Species Confirmation Standards

ISO 11133 (culture media quality assurance).
MALDI‑TOF MS – no single standard, but we follow validated manufacturer protocols.
16S rDNA sequencing – NCBI BLAST or ISO 11133 reference database.
Whole genome sequencing (WGS) – ISO 22940 (proposed).

3.3 Purity & Pathogen Absence Standards

USP <2022> (absence of specified microorganisms in probiotic products).
ISO 6579 (Salmonella).
ISO 11290 (Listeria monocytogenes).
ISO 16654 (E. coli O157).
China GB 4789.10 (Staphylococcus aureus).

3.4 Stability & Antimicrobial Susceptibility Standards

ICH Q1A (stability testing for pharmaceuticals – applicable to probiotic drugs).
EFSA guidance on characterisation of microorganisms used as feed additives (antibiotic resistance).
CLSI M45 (Methods for antimicrobial dilution and disk susceptibility testing of infrequently isolated or fastidious bacteria).

4. Why Choose Our Third‑Party Probiotics Testing Services?

As an independent laboratory with specialised expertise in live microorganisms, we provide accurate, reproducible, and regulation‑ready data. Our advantages include:

ISO/IEC 17025 accreditation – CNAS/CMA certified, regularly participating in proficiency testing (e.g., FAPAS, LGC, USP).
Anaerobic capability – dedicated anaerobic chambers (CO₂ / N₂ / H₂ atmosphere) for strict anaerobes (e.g., Bifidobacterium).
Strain differentiation – we can enumerate individual strains in multi‑strain products using selective media or molecular tools.
Low detection limits – viable counts down to 10 CFU/g; strain identification from single colony.
Fast turnaround – viable count enumeration in 3‑5 business days; strain identification in 5‑7 business days; full stability studies scheduled per customer requirement.
Comprehensive reporting – includes plate images, colony counts, identification results (MALDI‑TOF spectra, sequence alignment), and clear pass/fail against label claims or specifications.
Confidentiality – full protection of your product formulation, proprietary strains, and stability data.
Consultative support – our microbiologists help design stability protocols, interpret label claim compliance, and troubleshoot viability loss.

Whether you need to verify CFU count at release, confirm strain identity for regulatory submission, assess shelf‑life stability, or test for absence of contaminants, our probiotic testing experts are ready to deliver reliable results that support product efficacy and consumer trust.

Get Started with Your Probiotics Testing Project

Contact our team with your probiotic strain(s), product format (powder, capsule, liquid), target CFU claim, applicable standard (e.g., ISO, USP, GB), and any special requirements (stability, antimicrobial resistance). We will provide a detailed quotation, sample submission guidelines (including cold chain requirements for live cultures), and a testing schedule. Let us help you ensure that your probiotic products deliver the promised viable microorganisms – consistently, safely, and throughout shelf life.

This article provides an overview of our probiotic testing capabilities. For specific test methods, sample quantity, and pricing, please request a tailored service proposal.