What Is a Probiotic? Probiotic, Postbiotic and Parabiotic Guide

What is a probiotic?

The FAO/WHO definition of 2001 and the 2014 consensus statement of the International Scientific Association for Probiotics and Prebiotics (ISAPP) define probiotics as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." The definition rests on three conditions: the microorganism must be alive, present in an amount shown to have an effect, and identified at strain level.

Not every fermented food or every product containing bacteria is therefore a probiotic. Yogurt, kefir or pickles may contain live cultures, but the term probiotic is reserved for microorganisms identified at genus–species–strain level, with a defined viable count (CFU) and evidence at that dose.

The most studied groups are lactic acid bacteria (Lactobacillus and the genera split from it in 2020, Lactococcus, Streptococcus thermophilus), Bifidobacterium species, spore-forming Bacillus species and the yeast Saccharomyces boulardii.

Probiotic vs prebiotic vs postbiotic vs parabiotic

The four terms are often confused; the distinction rests on whether the component is alive and what it is:

• Probiotic: a live, identified microorganism. A defined viable count (CFU) must be maintained through shelf life.
• Prebiotic (ISAPP 2017): a substrate selectively utilised by host microorganisms conferring a health benefit, e.g. inulin or fructooligosaccharides. A nutrient source, not a microorganism.
• Postbiotic (ISAPP 2021): a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host. It contains inactivated cells, cell fragments and metabolites; since it does not depend on viability it is more stable to heat and over shelf life.
• Parabiotic (paraprobiotic): microbial cells inactivated by heat or other methods with their structure largely preserved. Often treated as a subset of postbiotics and used where live cultures cannot survive: hot filling, baking, cosmetic formulations.
• Synbiotic: a combination of a probiotic and a prebiotic.

What is a strain? Genus, species and strain naming

Microorganisms are named at genus, species and strain level: Lactiplantibacillus (genus) plantarum (species) LTC-Lp230198 (strain). Probiotic properties are largely strain-specific: two strains of the same species can differ in acid and bile tolerance, adhesion, metabolite production and technological robustness. Scientific literature and regulation therefore assess probiotic claims at strain level.

In 2020 the genus Lactobacillus was split into 25 genera on genomic grounds (Zheng et al., IJSEM). Lactobacillus plantarum became Lactiplantibacillus plantarum, L. rhamnosus became Lacticaseibacillus rhamnosus and L. reuteri became Limosilactobacillus reuteri. The Shymeriae strain catalog uses current nomenclature; former names are listed as synonyms in product documents.

Every strain carries a unique code in the culture collection, linked to its identification (16S rRNA and/or whole-genome sequencing), origin, storage and quality data, and stated on the certificate of analysis (CoA).

How is a probiotic raw material produced?

Industrial production turns a laboratory isolate into a standardised, reproducible and documented product through several steps:

• Isolation and identification: the strain is isolated from a natural source, identified by molecular methods, assigned a biosafety level (BSL) and deposited in the culture collection.
• Controlled fermentation: the strain is grown in a bioreactor on a defined medium under temperature, pH and oxygen control.
• Separation and preservation: cells are harvested by centrifugation, blended with a protective matrix and freeze-dried (lyophilised) to preserve viability. For postbiotic and parabiotic materials, controlled inactivation or extraction is applied at this stage.
• Coating and stabilisation: depending on the application, microencapsulation or coating improves resistance to gastric acid, moisture and heat.
• Quality control: every batch is tested for viable count (CFU/g), purity and contaminants (pathogens, yeast and mould, heavy metals) and released with a certificate of analysis (CoA) under GMP and ISO quality systems.

What to look for when sourcing a probiotic raw material

For formulators, the decisive criteria are:

• Strain-level identification and a culture collection deposit (a species name alone is not enough).
• Guaranteed viable count (CFU) at end of shelf life, backed by stability data.
• A form suited to the application: live freeze-dried culture, coated culture, postbiotic lysate or parabiotic cells.
• Biosafety level (BSL-1) and regulatory fit: in Türkiye, probiotic microorganisms in food supplements follow the Ministry of Agriculture and Forestry procedure; cosmetics, feed and agriculture have their own frameworks.
• Documentation: GMP and ISO certificates, batch CoA, technical data sheet and literature support.
• Supply continuity and technical support: working directly with the manufacturer on strain selection, dosage and formulation compatibility.

Why domestic probiotic production in Türkiye matters

Most probiotic raw material used in Türkiye is imported. Domestic production reduces import dependence, secures supply continuity and price predictability, allows the microbial diversity of Anatolia to be studied scientifically, and keeps strain development, fermentation and freeze-drying know-how in the country.

The Ministry of Agriculture and Forestry maintains a list of domestic culture collections for probiotic microorganisms used in food supplements. The Shymeriae Biotechnology culture collection is published on the official culture collection list, and its R&D project on using local microbial strains in traditional yogurt production is supported by KOSGEB.

Probiotic, postbiotic and parabiotic raw materials at Shymeriae

Shymeriae Biotechnology produces probiotic, postbiotic and parabiotic raw materials to GMP standards at 99.9% purity in Ataşehir, Istanbul. Every strain in the catalog is published with its code, product form, biosafety level and literature record, and every batch ships with a certificate of analysis. Formulation support is available for cosmetics, food supplements, food and beverage, animal nutrition and agriculture.

Frequently asked questions

What is the difference between a probiotic and a postbiotic?

A probiotic is a live microorganism that must stay viable in the product. A postbiotic is a preparation of inanimate (inactivated) microorganisms and/or their components; because it does not depend on viability it is more stable to heat and over shelf life.

What does CFU mean?

Colony forming units: the number of live, culturable microorganisms per gram or per dose. Probiotic raw materials are specified in CFU/g.

Is yogurt a probiotic?

Yogurt is fermented with the starter cultures Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. To be called probiotic, an identified probiotic strain must be added at an effective viable count.

Are probiotics heat-stable?

Most live cultures lose viability at high temperature; spore-forming Bacillus species are more robust. For baking or hot filling, postbiotic or parabiotic forms are preferred.

What does domestic (yerli) probiotic mean?

A probiotic raw material whose strain was isolated and characterised in Türkiye or which is manufactured at a facility in Türkiye. Shymeriae is a domestic manufacturer with its culture collection on the official registry.

Let us select the right strain for your formulation

Browse the strain catalog or ask our technical team for a sample and a quote.

References

1. Hill C. et al. (2014). ISAPP consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol.
2. Gibson G.R. et al. (2017). ISAPP consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol.
3. Salminen S. et al. (2021). ISAPP consensus statement on the definition and scope of postbiotics. Nat Rev Gastroenterol Hepatol.
4. Zheng J. et al. (2020). A taxonomic note on the genus Lactobacillus. Int J Syst Evol Microbiol.
5. Republic of Türkiye Ministry of Agriculture and Forestry, General Directorate of Food and Control — Application Procedure for Food Supplements Containing Probiotic Microorganisms and Postbiotics.