CFU means colony forming units — the number of live microorganisms in a serving. A 40 billion CFU product contains four times as many as a 10 billion one. It is not automatically better: strain selection, survival through stomach acid, and whether the count is guaranteed to the end of shelf life all matter alongside the number.
1. What CFU actually means
CFU stands for colony forming units. It is a counting method borrowed from microbiology: a sample is spread on a growth medium, and each microorganism capable of multiplying forms one visible colony. The number of colonies gives the count.
Two things follow from that, and both matter when you are comparing labels.
First, CFU counts only living microorganisms. Dead cells form no colony and are not counted. This is why the figure is tied to storage and shelf life rather than being fixed at the point of manufacture forever.
Second, CFU is a measure of quantity, not of identity or quality. It tells you how many, not which ones. Two products can both declare 10 billion CFU and contain entirely different organisms.
The unit also covers yeasts as well as bacteria. Saccharomyces boulardii, which appears in some live-culture supplements, is a yeast rather than a bacterium, and is still counted in CFU.
2. 10 billion vs 40 billion: the actual difference
Arithmetically the difference is simple — 40 billion is four times 10 billion. In practice, products at these two counts usually differ in more than the number, because formulators tend to change the strain line-up at the same time.
Here is how the two JeaKen live-culture formulations compare on composition alone:
| 10 billion CFU formula | 40 billion CFU formula | |
|---|---|---|
| Cultures per serving | 10 billion CFU | 40 billion CFU |
| Number of strains | 6 | 23 |
| Notable inclusion | Saccharomyces boulardii (a yeast) | 23 named cultures, including Saccharomyces boulardii |
| Prebiotic | Inulin | Inulin |
| Capsule | Standard capsule | Delayed-release capsule |
| Pack | 90 capsules | 60 capsules |
The delayed-release capsule is worth understanding, because it is a formulation choice rather than a marketing one. Stomach acid is hostile to many live cultures. A capsule designed to open lower down the digestive tract is one way of addressing that; selecting acid-resistant organisms is another. Both approaches appear across the category.
3. Is more CFU always better?
No. A higher count is more of the same thing, and more is only useful if the thing itself is appropriate.
Research on live cultures is overwhelmingly strain-specific. Studies are conducted on individual, named strains at particular doses — not on the category as a whole, and not on CFU counts in the abstract. A finding for one strain does not transfer to a different strain, even a closely related one from the same genus. This is the single most important thing to understand about the evidence base, and it is why a raw CFU number tells you much less than it appears to.
It also means the useful question is not “how many?” but “how many of what?”
4. How many CFU should a probiotic have?
There is no established universal threshold, and no regulator publishes a recommended CFU intake. Products on the UK market commonly range from around one billion to over one hundred billion CFU per serving.
Because the research is strain-specific, the meaningful comparison is between a product and the dose used in studies of the strains it actually contains — not between one product’s total and another’s.
5. CFU or strains: which matters more?
They answer different questions. CFU is quantity. Strain count is diversity. Neither is a quality score on its own.
Most supplement strains come from two bacterial genera. Lactobacillus species are predominantly associated with the small intestine, and Bifidobacterium species with the large intestine. A multi-strain formula typically draws from both. Some products also use spore-forming or soil-based organisms, which are naturally more resistant to stomach acid.
A larger number of strains means broader coverage of different organisms. It does not mean each individual strain is present at a meaningful dose — a 23-strain product divides its total count across 23 organisms, so any single one is present in a smaller amount than it would be in a formula of six. Neither arrangement is inherently superior; they are different design choices.
6. What to look for on a live-culture label
- Full strain names, not just genus. A properly identified strain has three parts — genus, species and strain designation, for example Lactobacillus rhamnosus GG. Genus alone tells you very little.
- CFU per serving, and what a serving is. Check whether the figure is per capsule or per two capsules.
- When the CFU count is guaranteed — see the next section.
- Whether a prebiotic is included. Prebiotics are fibres that act as a substrate for the cultures. A product combining both is described as a synbiotic.
- Capsule type — standard, delayed-release or enteric-coated.
- Storage instructions. Some products are shelf-stable, others need refrigeration. The pack will say.
- Allergens and capsule material — relevant if you need a vegan or gelatine-free product.
7. Does the CFU figure apply at manufacture or at the end of shelf life?
This is the most consequential detail on a live-culture label, and the one most often left unstated.
Live cultures decline over time. A count measured on the production line will be higher than the count in the same capsule eighteen months later. Manufacturers can therefore declare CFU in two different ways:
- At time of manufacture — the number when the batch was made. The amount remaining at the end of shelf life is not stated.
- Through end of shelf life, sometimes labelled “guaranteed to expiry” — the minimum count remaining at the best-before date. This is the more informative declaration, because it is the number you can rely on for the whole life of the pack.
A product declaring 40 billion at manufacture and one declaring 40 billion at expiry are not making the same statement, and there is no way to tell them apart unless the label says which.
For transparency: JeaKen’s own product pages state CFU per serving but do not currently specify which of these two measures is used. If that matters to your decision, it is worth asking any manufacturer directly — including ours.
8. Probiotics and the rules on claims
You may notice that this article describes what these products contain, and does not tell you what they do. That is deliberate, and it reflects the regulatory position rather than an oversight.
In Great Britain, health claims on foods and food supplements may only be made if they appear on the GB Nutrition and Health Claims Register. No health claim for any probiotic or live culture is currently authorised on that register. Applications submitted under the EU framework, which GB rules derive from, were not approved by the European Food Safety Authority. The term “probiotic” has itself generally been treated in the EU as an implied health claim, which is why many products in this category are sold and labelled as “live cultures” instead.
So any page telling you what a probiotic will do for your health is going beyond what the rules permit. What can be stated accurately is composition: which organisms, how many, in what format, with what else.
9. The two JeaKen live-culture formulations
Both are manufactured in the UK and combine live cultures with prebiotic fibre.
- JeaKen 10 Billion CFU formula — six cultures at 10 billion CFU per serving, including Saccharomyces boulardii, with prebiotic inulin. 90 capsules.
- JeaKen 40 Billion CFU formula — 23 cultures at 40 billion CFU per serving with prebiotic inulin, in delayed-release capsules. 60 capsules.
You can also compare JeaKen live-culture formulations alongside the rest of the fibre and live-culture range.
Common questions
What does CFU mean?
CFU stands for colony forming units — the number of live microorganisms in a serving that are capable of multiplying. It counts living organisms only, and it measures quantity rather than which organisms are present.
Is 40 billion CFU better than 10 billion?
Not automatically. It is four times as many live cultures, but research on live cultures is strain-specific, so which organisms are present matters alongside how many. A higher count is more of the same thing, and more is only useful if the organisms are appropriate.
How many CFU should a probiotic have?
There is no established universal threshold and no regulator publishes a recommended CFU intake. Products on the UK market commonly range from around one billion to over one hundred billion CFU per serving.
What matters more, CFU or strains?
They answer different questions. CFU is quantity; strain count is diversity. Neither is a quality score by itself. Because studies are conducted on named individual strains, the identity of the organisms is generally more informative than the total count.
Are more probiotic strains better?
More strains means broader coverage of different organisms, but a fixed total count divided across more strains means less of each individual one. A 23-strain formula and a 6-strain formula are different design choices rather than better and worse versions of the same thing.
Does the CFU count apply at manufacture or at the end of shelf life?
It depends on the manufacturer, and the label should say. A count declared at time of manufacture will be higher than the count remaining at the best-before date. A count guaranteed through end of shelf life is the more informative declaration. Where a label does not specify, it is worth asking the manufacturer.
What is the difference between a probiotic and a prebiotic?
Probiotics are live microorganisms. Prebiotics are dietary fibres, such as inulin, that act as a substrate for them. A product containing both is described as a synbiotic.
Do live-culture supplements need refrigerating?
Some do and some are formulated to be shelf-stable. The storage instructions on the pack are the reliable guide, and following them matters because CFU counts living organisms only.
Why does this page not say what probiotics do?
Because no health claim for any probiotic or live culture is currently authorised on the GB Nutrition and Health Claims Register. Claims outside that register may not be made for food supplements in Great Britain, so this article describes composition instead.
Sources and further reading
These sources are cited for definitions, scientific context and regulatory context. None of them evaluates or endorses any JeaKen product.
- Hill C. et al. (2014), “The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic”, Nature Reviews Gastroenterology & Hepatology — the ISAPP consensus, including the principle that evidence is strain-specific.
- Gibson G.R. et al. (2017), “Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics”, Nature Reviews Gastroenterology & Hepatology.
- FAO/WHO (2001–2002) — the joint expert consultation that produced the widely used definition of probiotics as live microorganisms administered in adequate amounts.
- GB Nutrition and Health Claims Register, Department of Health and Social Care — the list of health claims permitted on foods and food supplements in Great Britain.
- European Food Safety Authority (EFSA) — opinions on health claim applications relating to gut microorganisms, and the general scientific requirements for substantiating a health claim.
