How scientists track the bacteria that make yogurt and kefir and keep us healthy
If you’ve ever read the back of a probiotic supplement pack, you’ve probably seen long, complicated names like Lactobacillus bulgaricus, Streptococcus thermophilus, and Bifidobacterium longum.
In some cases, you may also see strange numbers next to it, such as NBIMCC 8244 or DSM 17938. These codes may seem like random research jargon, but they’re actually like hidden microbial passports, or microbial ID cards. These help scientists know exactly which live strain is being used and where it came from.
What is “strain”?
Although all dogs belong to the same species, Canis Familyis, Chihuahuas and German Shepherds are very different. The same goes for bacteria. Two microorganisms may share the same name, but behave very differently depending on their lineage. This is why scientists use the word “stock.” This means a specific version of a species with its own characteristics and personality. For example, any strain of B. bulgaricus can make yogurt, but some give it a thicker texture, some give it a tangier flavor, and some survive better in the intestines. Strain identity is really important. Not all members of the same species do the same job.
Why do bacteria have strain numbers?
When scientists isolate a new bacterium (perhaps from milk, plants, or human sources), they send it to a microbial bank. Each culture is stored in a small frozen or lyophilized tube and given a unique strain number, or permanent identification tag. for example:
– Lactobacillus bulgaricus NBIMCC 8244
– Streptococcus Thermophilus NBIMCC 8253 The letters indicate in which “library” it is kept.
– DSMZ – German microbial and cell culture collection
– ATCC – American Type Culture Collection
– JCM – Japanese Microbial Collection. When researchers and food producers need a specific microorganism, they can order by number, just like borrowing the exact book from a worldwide catalog.
– NBIMCC – National Bank of Industrial Microbiology and Cell Culture (Bulgaria)
“belonging to” and “similar to”
Scientific documents sometimes state that one strain “belongs to” or is “similar to” another. This is more than just a quirk of language, it shows how closely related different cultures are.
• Belonging to (or equivalent to) means that it is the same isolate kept in multiple collections. The bacteria initially deposited in Bulgaria may later be sent to Germany and receive a new DSM number, but it is still the same strain.
• Similar means different isolates of the same species. Although these bacteria share many characteristics and behave similarly, they are not identical and are more like cousins than twins. This difference is important. If the two cultures are truly the same strain, the safety and performance data for one can be applied to the other. If it’s only similar, you’ll need your own testing.
Why the number of shares is important
A stock number is more than just a technical detail. We ensure that the bacteria used in our food and probiotics are authentic, safe, and consistent. Without these, no one can be sure which microorganisms are in your starter or supplement.
– Traceability – We know where the culture comes from.
– Consistency – the same microorganisms are used in every batch.
– Safety – Only food grade approved strains are used.
The European Food Safety Authority (EFSA) maintains a Qualified Presumptive Safety List of microorganisms that have been used safely for a long time, including Lactobacillus, Bifidobacterium and Streptococcus thermophilus. In the United States, a similar strain is listed as GRAS (Generally Recognized as Safe).
Role of NBIMCC stock
Based in Sofia, Bulgaria, NBIMCC maintains a rich collection of traditional and modern microbial strains used in yogurt, kefir, and other fermented foods. Examples include:
– Lactobacillus delbrueckii ssp. bulgaricus NBIMCC 8244
– Streptococcus thermophilus NBIMCC 8253
– Lactobacillus reuteri NBIMCC 8777
These cultures are part of a long tradition in dairy fermentation in this country and are valued by scientists for their safe and beneficial properties. They are food grade, non-pathogenic and used in starter cultures in Europe and other countries.
An easy way to think about it
Imagine two bakers making sourdough bread. One uses some of the original starters that have been passed down through generations. It’s the same stock. The other is to create a similar starter from scratch. This is a similar stock. Both bake delicious bread, but only one has the exact “lineage” of microorganisms. The same goes for bacteria. Strain numbers ensure that what scientists and producers are using today is the same reliable culture as yesterday.
A global network of microbial libraries
Hundreds of collections around the globe, from the United States and Japan to Germany and Bulgaria, are helping preserve microorganisms. They share information through the World Cultural Collections Federation (WFCC) to ensure that beneficial microorganisms remain accessible, traceable, and safe for generations to come. Each small tube stored in the freezer represents more than just a cell culture, it is a piece of scientific heritage and a time capsule of life.
Why strain numbers are rarely displayed on commercially available yogurt
Most yogurts found in stores do not have the exact strain number listed on the bottle. Actually, there is a good reason for this.
When we talk about “strains,” we mean specific genetic versions of bacteria, each registered in a microbial collection with a unique ID number. bulgarian lactic acid bacteria NBIMCC 8245 or L. reuteri DSM 17938. These numbers are primarily used in science to ensure that everyone is talking about the same organism, since different strains within the same species can behave completely differently.
However, food labeling laws do not require yogurt producers to go into such detail. They just need to say what species of bacteria is present. for example, bulgarian lactic acid bacteria and thermophilus — Two classic yogurt starters.
Strain number statements are only required for probiotic products that make specific health claims such as “supports digestion” or “improves intestinal flora.” This is because these claims must be based on clinical studies associated with the exact strain.
There is also a commercial aspect. Most yogurt companies use proprietary starter blends developed over many years to achieve the right taste, texture, and aroma. The exact strain is part of the trade secrets and is therefore treated as a secret.
Additionally, industrial yogurts often use multiple strains in combination, and their blends can change slightly over time, making detailed labeling confusing and complicated to maintain consistency.
Strain numbers are only displayed in certain probiotic drinks and supplements, such as Yakult (L. casei Shirota) or Activia (Bifidobacterium animalis subspecies Ractis BB-12) — because these products are based on specific, well-studied strains of bacteria with proven health effects.
In other words, yogurt doesn’t have a strain number on it simply because it doesn’t need to, and the details are more relevant to scientists and probiotic manufacturers than everyday consumers. The most important thing about regular yogurt is that it’s made with live, active cultures, even if the exact strains remain behind the scenes.
conclusion
The mysterious codes on yogurt labels and scientific papers aren’t random. They are part of the international system that keeps our food, medicines and research reliable.
So the next time you open a pot of yogurt, keep that in mind. Inside are millions of useful little microbes, each with its own passport, kept safe and recorded in the global library of life.
