On a label, you see a Latin name followed by a set of letters and numbers, for example DSM 15693. This is not a random code or part of marketing. Such a code points to a specific, deposited line of bacteria. It lets you check whether a product and a scientific publication talk about the same material.
Three levels of naming: genus, species, strain
The full name of a microorganism has three levels. The genus is the first part of the Latin name and the species is the second part. The strain is a code that points to one single isolated line.
Take the name Limosilactobacillus reuteri DSM 15693. Limosilactobacillus is the genus, reuteri is the species, and DSM 15693 is the strain designation from a culture collection. One example of a product that gives the full designation in this form is THESYBIN food supplement.
Read more: Limosilactobacillus reuteri – the story of a strain that changed its name
These levels differ in how precise they are. The species name points to a group of related microorganisms. The strain designation refers to one line that has been described and is stored in a form that can be reproduced.
What culture collections of microorganisms are
Culture collections are institutions that store isolated lines of microorganisms in conditions that keep them stable. Most often, they use freeze-drying (lyophilisation) or storage at very low temperatures.
Each deposited strain gets a catalogue number and a description of its origin, its features and its growing conditions. Collections make strains available for research and industrial use. This means that another team can work on the same material.
The abbreviation before the number shows which collection it is. The same strain is sometimes deposited in several collections at once. In that case, it has several equal designations.
The most common abbreviations on labels
| Abbreviation | Full name of the collection | Country |
|---|---|---|
| DSM | Deutsche Sammlung von Mikroorganismen und Zellkulturen | Germany |
| ATCC | American Type Culture Collection | United States |
| CNCM | Collection Nationale de Cultures de Micro-organismes (Pasteur Institute) | France |
| LMG | BCCM/LMG Bacteria Collection (Ghent University) | Belgium |
| NCIMB | National Collection of Industrial, Food and Marine Bacteria | United Kingdom |
| CECT | Colección Española de Cultivos Tipo | Spain |
Why a strain is deposited in a collection at all
The first reason is that research must be repeatable. A publication that describes the properties of a strain only has value if another team can get the same strain and check the result. Without a deposit, nobody can check it.
The second reason is identification. The catalogue number works as an identifier. It shows whether the strain described in a scientific paper and the strain used in a product are the same line, whatever the trade name is.
The third reason is that the material stays stable. The collection stores the strain in conditions that limit changes. So the material that it provides years later matches the material that was deposited.
A separate topic is the deposit of microorganisms for patent procedures. The Budapest Treaty of 1977 regulates this, and Poland joined it in 1993. The details of this procedure are outside the scope of this text.
Why two strains of the same species can have different properties
Bacteria of one species share basic features, but they do not have identical genomes. The genome is all the genetic material of a cell. The differences are about whether certain genes are present or not. This affects which compounds a line can produce.
This has practical results. Two strains of the same species can produce different metabolites and grow at different speeds. They can also differ in how well they resist low pH and in how they behave in production. Metabolites are the products of chemical changes in the cell.
For this reason, in microbiology the features described in studies are considered a property of a specific strain, not of the species. The ISAPP consensus statement on probiotics from 2014 states this rule directly. ISAPP (the International Scientific Association for Probiotics and Prebiotics) is an international scientific association that works on this subject.
The same requirement appears in the ISAPP statement from 2021 about inanimate preparations: the source microorganism must be described at the level of the strain, not only the species.
What should make you look more carefully at a label
The list below describes how things work, not specific products or brands. These signs do not decide the quality, but they are a reason to look at the description more closely.
- No strain designation. Only the genus and species names are given, without a code from a collection. This makes it impossible to link the product to any publication.
- Only the genus name. The description only says something like “bacterial cultures”, or gives only the first part of the Latin name.
- A code without a collection abbreviation. There is a string of numbers or letters without a prefix that shows the collection, so you cannot check the deposit.
- The description and the declared amount do not match. The name suggests live cultures, but the content is given in units of mass. Or the opposite: the description talks about an inanimate preparation, but the declared amount is in CFU (colony-forming units).
- References to studies without the strain. The materials refer to studies on the species but do not say which strain the studies were about.
- No information about the amount per portion. The ingredients are listed without reference to the recommended daily portion of the product. Read more: How to read the ingredients of a food supplement – what to look at beyond the marketing name
Remember that in Poland, food supplements are supervised under different rules than medicines. The label is still the main source of information for the people who buy them.
Read more: How food supplements are supervised in Poland – notification, GIS and producer obligations
Summary
The code after the Latin name is a catalogue number from a culture collection of microorganisms. It points to a specific, deposited line of bacteria. It lets you check whether a product and a scientific publication refer to the same material.
This matters because the properties described in studies are a feature of a specific strain, not of the whole species. Two lines of the same species can differ in their genome and in the compounds they produce.
So when you compare products, the full strain designation is more useful information than the species name alone. If it is missing, this does not decide the quality, but it limits your ability to check the product yourself.
FAQ
Does a missing strain number mean that a product is worse?
Not necessarily, but it makes it harder to check the information. Without a designation, you cannot link what the product contains to specific publications. You also cannot compare it with another preparation based on the same species.
Can the same strain have several different numbers?
Yes, if it was deposited in more than one collection. Manufacturers then usually give one designation, less often two equal ones. You can find information about the others in the catalogues of the collections.
Where can you check what a designation refers to?
The main source is the catalogues of culture collections, which are available on the websites of these institutions. You can also type the full designation into a search engine for scientific publications. This shows whether the strain has been studied and what type of studies they were.
Sources
- Hill C., Guarner F., Reid G. et al., Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic, Nature Reviews Gastroenterology & Hepatology, 2014, vol. 11, no. 8, pp. 506-514.
- Salminen S., Collado M.C., Endo A. et al., The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics, Nature Reviews Gastroenterology & Hepatology, 2021, vol. 18, no. 9, pp. 649-667.
- Zheng J., Wittouck S., Salvetti E. et al., A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae, International Journal of Systematic and Evolutionary Microbiology, 2020, vol. 70, no. 4, pp. 2782-2858.
- Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health.
- The LPSN database (List of Prokaryotic names with Standing in Nomenclature) run by DSMZ, https://lpsn.dsmz.de, and the catalogues of culture collections of microorganisms (DSMZ, ATCC, CNCM, LMG, NCIMB, CECT).
- Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure and Regulations under the Budapest Treaty, done at Budapest on 28 April 1977 (Journal of Laws of the Republic of Poland, Dz. U. 1994, No. 110, item 528).