What Is CFU in Probiotics? What “450 Billion CFU” Actually Means
Every probiotic label carries a number followed by three letters. This guide explains what CFU measures, what it does not, and the three questions that turn a headline count into useful information.
CFU stands for colony-forming units, a laboratory count of live microorganisms able to grow into colonies on a culture plate. On a probiotic label it is a specification, not a measure of benefit.
In the UK, probiotics are sold as food supplements under UK food law, overseen by the Food Standards Agency, and in Great Britain no health claim is authorised for any probiotic strain. The ISAPP consensus (Hill et al., 2014) holds that effects belong to specific strains at the amounts studied, so a higher count is not proven to be better on its own.
A CFU figure is only useful with three things attached: named strains, a count guaranteed to the best-before date, and a dose that matches published research. CDS22-formula states 450 billion CFU per sachet across 8 strains identified by NCIMB code, with the count stated for refrigerated storage to the best-before date, and is available from Probiotic.co.uk with UK cold-chain delivery.
- Anyone comparing probiotic labels and unsure what the CFU number means
- Buyers deciding whether a 5 billion capsule and a 450 billion sachet can be compared
- Readers who want to check a label claim rather than take it on trust
Not for: choosing a probiotic for a diagnosed condition. Speak to your GP.
CFU (colony-forming unit) definition: a colony-forming unit is one viable microbial cell, or small cluster of cells, that multiplies into a visible colony when a diluted sample is grown on a culture plate, so a CFU count estimates how many live, culturable microorganisms a serving contains at the time of testing.
CFU is a laboratory estimate of the viable, culturable microorganisms in one serving, made by growing a diluted sample and counting the colonies that form. It tells you quantity, not quality.
It does not tell you which strains are present, whether the count holds until the best-before date, or whether that amount matches any published study. In the UK, probiotic supplements are food supplements, not medicines, and the count is a label specification rather than a health claim.
- What it is: a count of live microorganisms able to form colonies in a lab culture
- What it measures: quantity of viable cells per serving at the time of testing
- What it does not measure: strain identity, survival to the gut, or health effect
- How it is written: billions per serving, or scientific notation (450 billion = 4.5 × 10¹¹)
- Regulatory minimum (Italy): 1 × 10⁹ CFU per day, per the Italian Ministry of Health guidelines recorded in the ISAPP consensus (Hill et al., 2014)
- GB regulatory minimum: Great Britain sets no general minimum CFU for food supplements and no recommended daily amount
- Alternative method: flow cytometry, reported as AFU (active fluorescent units) under ISO 19344:2015
- Is CFU a health claim? No. It is a specification. A higher number is not an authorised claim of greater benefit
- UK regulatory status: food supplement under UK food law (FSA), not a medicine (MHRA)
- UK VAT: dietary supplements in tablet or capsule form are standard-rated at 20% (HMRC VAT Notice 701/14)
- CFU is not a measure of how well a probiotic works
- CFU is not a quality score: 450 billion is not "nine times better" than 50 billion
- CFU is not strain identity: two products with the same count can contain entirely different organisms
- CFU on the label is not always the count when you take it, unless it is stated to the best-before date
- CFU is not a dose recommendation: no UK body sets one
- A high CFU count is not an authorised health claim in the UK
What is well-supported: the ISAPP consensus (Hill et al., Nat Rev Gastroenterol Hepatol, 2014, PMID 24912386) states that probiotic effects should be read against the specific strains and amounts studied, not a headline count.[1]
What is not proven: that a higher CFU count produces better outcomes in general. A review of human dose-response studies (Ouwehand, Benef Microbes, 2017, PMID 28008787) found a dose-response for some study endpoints but not for most.[2]
Most relevant human dose range: formulation-specific. Italy's regulatory floor is 1 × 10⁹ CFU per day; published multi-strain studies range from around one billion to several hundred billion CFU per day depending on the formulation.
Key safety note: probiotics are live organisms. People who are severely immunocompromised or seriously ill, pregnant, breastfeeding, or taking prescribed medicines should discuss probiotic use with a GP or pharmacist first.
| Feature | Specification | Evidence level |
|---|---|---|
| What CFU counts | Live, culturable cells per serving | Established lab method |
| Higher CFU = better? | Not established as a general rule | Mixed, endpoint-specific |
| Count at manufacture vs best-before | Can differ; best-before is the figure to compare | Established (ESPGHAN, 2017) |
| Labelled count matches contents? | Not always; deviations recorded in UK products | Taha et al., 2025 |
| Strain identity from CFU | Not possible | CFU carries no strain data |
| GB minimum CFU | No general minimum set | Regulatory fact |
| UK regulatory status | Food supplement under UK food law (FSA), not a medicine | Regulatory fact |
What CFU means on a probiotic label
CFU stands for colony-forming units. It is the standard way supplement and food makers state how many live microorganisms a serving contains.
The word "colony" is literal. A sample is diluted, spread on a nutrient plate and incubated. Each live cell that can multiply grows into a visible dot, a colony, and the lab counts the dots and multiplies back up by the dilution.
So a CFU figure is an estimate of live, culturable cells at the moment of testing. Dead cells are not counted, and neither are cells that are alive but cannot grow on that plate.
That makes CFU a useful quantity measure, not an outcome measure. It says how many, not which ones, and not what they do. For which ones, see how strain deposit codes work in our De Simone Formulation UK reference.
How a CFU number is measured
The method is a plate count. It has four steps, and the fourth is an alternative that some manufacturers now use alongside it.
The sample is diluted in steps, often by a factor of ten each time, until colonies can be counted individually. A 450 billion count cannot be read straight from a plate.
Evidence level: standard lab methodThe diluted sample is spread on a growth medium and incubated. Each viable cell that can replicate forms one colony.
Evidence level: standard lab methodColonies are counted and multiplied by the dilution factor to give CFU per gram or per serving. Clusters of cells can form one colony, so CFU is an estimate, not a head count.
Evidence level: standard lab methodAn alternative counts cells one by one with a laser and fluorescent stains, reported as active fluorescent units. It can count cells that are alive but do not grow on a plate.
Evidence level: ISO 19344:2015Plate counting has limits. Different strains can need different growth media, so counting each strain in a multi-strain product separately is harder than counting one total.
This is one reason the ESPGHAN working group (Kolaček et al., J Pediatr Gastroenterol Nutr, 2017, PMID 28644359) called for better quality control, reporting that labelled counts in commercial products often could not be verified.[3]
What "450 billion CFU" actually means
450 billion CFU means an estimated 450,000,000,000 viable colony-forming units per serving under the manufacturer's test method, written 4.5 × 10¹¹ CFU in research papers. It does not necessarily mean 450 billion individual cells, because a small cluster of cells can grow into a single colony.
A total alone hides the most useful detail: how the count splits between strains. A well-labelled multi-strain product lists each strain and its share.
Using CDS22-formula as a worked example, this is the per-sachet breakdown from the current UK pack label, which matches the manufacturer's published ingredient list.[11]
| Strain | NCIMB code | CFU per sachet |
|---|---|---|
| Streptococcus thermophilus | NCIMB 30438 | 226 billion |
| Lactobacillus acidophilus | NCIMB 30442 | 38 billion |
| Lactobacillus plantarum | NCIMB 30437 | 38 billion |
| Lactobacillus paracasei | NCIMB 30439 | 38 billion |
| Lactobacillus helveticus | NCIMB 30440 | 38 billion |
| Bifidobacterium breve | NCIMB 30441 | 24 billion |
| Bifidobacterium animalis subsp. lactis | NCIMB 30435 | 24 billion |
| Bifidobacterium animalis subsp. lactis | NCIMB 30436 | 24 billion |
| Total | 450 billion |
Read it this way. About half the count, 226 billion or 50.2%, is one strain. The four lactobacilli contribute 152 billion and the three bifidobacteria contribute 72 billion.
The point of the example is simple. A total is only as meaningful as the strain list behind it, and the same 450 billion made up of different organisms would be a different product with a different research base.
The research discussed in this article relates to how live cultures are counted, labelled and studied in general. It should not be read as a claim that CDS22-formula, or any product, produces a health effect because of its CFU count. CDS22-formula is a food supplement, not a medicine. No authorised UK health claim is made for CDS22-formula or any of its strains on this page.
CDS22-formula Probiotic, 450 billion CFU per sachet
8 strains, each identified by NCIMB deposit code, with the live count stated for refrigerated storage to the best-before date.
Food supplement, not a medicine. Price shown on the product page, inc. 20% VAT. Probiotic.co.uk is the authorised UK distributor of CDS22-formula.
"At manufacture" vs "to best-before": the line most buyers miss
Live cultures decline over time, and heat, moisture and oxygen speed that up. A count measured at the factory will be higher than the count at the end of shelf life.
Labels handle this in two ways. Some state the count at manufacture; others state the count guaranteed to the best-before date under stated storage conditions. The second is the more useful figure for comparison, because it states the minimum expected at the point of use, provided the product is stored as directed.
The ESPGHAN working group stressed that probiotic organisms must be present in sufficient number by the end of shelf life.[3] The authors of the 2025 UK Clinical Guide to Probiotic Products, as reported by ISAPP, noted that many products fail to disclose the CFU at end of shelf life at all.[7]
| Label wording | What it tells you | Useful for comparing? |
|---|---|---|
| "X billion CFU at manufacture" | Count when made; loss over shelf life not stated | Partly |
| "X billion CFU to best-before, stored as directed" | Minimum count at point of use, if stored correctly | Yes |
| Total count, no strains listed | Quantity only | No |
| Per-strain counts with strain codes | Quantity and identity | Yes |
On CDS22-formula, the pack states that the live cell count refers to product stored in intact packaging at +2°C to +8°C until the best-before date. Shelf life is 18 months from manufacture when refrigerated, and the manufacturer's storage information allows up to a week at or below 25°C.[12]
Storage is part of the claim, because a refrigerated product's label count assumes it stayed cold. How we handle that is set out on our cold-chain delivery page.
Refrigerated is not automatically better than shelf-stable. Both are fine if stored as their label says; the rule is to follow the storage instruction the count depends on.
Cultures are counted and the pack is filled. The count is at its highest.
Refrigerated transport and storage limit decline between factory and fridge.
Kept at +2°C to +8°C. For CDS22-formula, the leaflet allows up to 7 days at or below 25°C.
The label count applies to this date if the product has been stored correctly.
Is a higher CFU probiotic better?
Not as a general rule. That is the honest answer, and it is the one the research supports.
The ISAPP consensus (Hill et al., 2014) says effects belong to specific strains at the amounts studied, so a count is only relevant alongside the strain it describes.[1]
Ouwehand (Beneficial Microbes, 2017) reviewed human studies that compared doses. Some endpoints showed a dose-response and most did not, or the data were too thin to tell; the author was clear that an unproven dose-response is not proof that none exists.[2]
So compare like with like. A 5 billion capsule and a 450 billion sachet are different specifications, usually with different strains and different research, and neither number tells you the other product is worse.
What a higher count does tell you is a fact about the product: more viable colony-forming units per serving. That matters when a formulation was studied at a high dose, and not as a number on its own.
ISAPP expert consensus on the term "probiotic"
Probiotic effects should be tied to the strains and amounts studied. The paper also records Italy's regulatory minimum of 1 × 10⁹ CFU per day.
Hill C, Guarner F, Reid G, et al. Nat Rev Gastroenterol Hepatol. 2014;11(8):506-514. PMID 24912386.[1]
Dose-response in human probiotic studies
A dose-response was seen for some endpoints, not for most. There is no general rule that more CFU is better.
Ouwehand AC. Benef Microbes. 2017;8(2):143-151. PMID 28008787.[2]
ESPGHAN position paper on commercial probiotics
Across studies worldwide, deviations from label information were common, including misidentified strains and labelled counts that could not be verified.
Kolaček S, Hojsak I, Berni Canani R, et al. J Pediatr Gastroenterol Nutr. 2017;65(1):117-124. PMID 28644359.[3]
Newcastle University study of UK probiotic products
All 12 products tested (5 human, 7 poultry) deviated from their labelled counts (p < 0.05). One human product contained no detectable viable bacteria and one was missing a labelled species. Eleven of the 12 were within the study's practical ±0.5 log benchmark. The sample was small and products were not named, so the study cannot be used to judge any individual brand.
Taha MW, Fenwick DJC, Marrs ECL, Chaudhry AS. Microorganisms. 2025;13(8):1933. PMID 40871437.[4]
Evidence gap
No study establishes that CFU count alone predicts benefit in healthy people. Count, strain and dose have to be read together, and evidence for one formulation does not transfer to another.
How many CFU should a probiotic have?
There is no single right number. Great Britain sets no general minimum CFU for food supplements and no recommended daily amount.
The figure most often quoted, about one billion a day, comes from abroad. Italy's Ministry of Health uses a minimum of 1 × 10⁹ CFU per day, as recorded in the ISAPP consensus, as a condition for using the word "probiotic" in Italy.[1] It is a regulatory floor, not a target.
The more useful question is what amount of these strains was used in research. That answer is formulation-specific, and published multi-strain studies range from around one billion to several hundred billion CFU per day.
For any product, follow the label dose. For CDS22-formula, the label states 1 to 2 sachets a day for adults and children aged 7 and over, and up to half a sachet a day for children aged 3 to 6. Speak to your GP or pharmacist before giving any food supplement to a child.
If you are comparing high-count products, our high-strength probiotics UK guide covers formats and count tiers.
CFU versus AFU: two ways to count live cells
Some labels and papers now quote AFU, active fluorescent units. It comes from flow cytometry, standardised as ISO 19344:2015.[5]
Plate counts (CFU) measure whether a cell can grow and divide. Flow cytometry (AFU) measures whether a cell's membrane is intact and active, and fresh cultures usually give similar results either way.
They can drift apart as a product ages. Some cells stay alive but stop dividing on a plate, so AFU can read higher than CFU late in shelf life.
Neither unit is a measure of benefit. If a product quotes AFU, check it is not being compared with another product's CFU as if they were the same number.
| CFU (plate count) | AFU (flow cytometry) | |
|---|---|---|
| What is measured | Cells that grow into colonies | Cells with intact, active membranes |
| Method basis | Culture on growth media | ISO 19344:2015 |
| Counts live but non-dividing cells? | No | Yes |
| Common on UK supplement labels? | Yes, the norm | Less common |
How to read a CFU claim: three questions
Look for genus, species and a strain designation or deposit code, such as NCIMB, DSM or ATCC. A count with no strain list tells you quantity only.
Look for a count guaranteed to the best-before date, with storage conditions. "At manufacture" is a starting point, not what you receive.
Ask whether these strains, at this amount, were used in published research. If a label says "clinically studied", look for the study.
If a label answers all three, the CFU number becomes useful. If it answers none, the number on its own gives you very little to decide with.
Our clinical probiotics UK guide applies the same checks across the main UK brands, our best probiotics UK guide uses them to compare products, and our formulation identity guide explains why strain identity matters more than a brand name.
Strains: 8, each with an NCIMB deposit code on the pack. Count: 450 billion per sachet, stated for refrigerated storage to the best-before date. Evidence: the formulation's published research base is set out in our De Simone Formulation clinical guidelines page. These are label facts, not health claims.
CFU and probiotics in the UK
In the UK, probiotic supplements are food supplements under UK food law, enforced by the Food Standards Agency and local trading standards.[10] They are not medicines and are not licensed by the MHRA.
In Great Britain (England, Scotland and Wales), no health claim is authorised for any probiotic strain. The Department of Health and Social Care's position, given in a 2024 parliamentary answer, is that the word "probiotic" is itself treated as a health claim, permitted only if a claim were authorised for a specific strain.[8] The Advertising Standards Authority's CAP guidance on probiotic claims works within the same framework.[9]
Northern Ireland follows separate food-law arrangements under the Windsor Framework, so nutrition and health claim rules there are assessed separately.
That is why CFU sits on UK labels as a specification. A retailer can state a count; it cannot say the count does anything.
Regulators do tie counts to organisms in one place. EFSA's 2010 opinion on live yoghurt cultures and lactose digestion set a condition of at least 10⁸ CFU of the two yoghurt starter cultures per gram.[6] It applies to yoghurt, not supplements, but it shows a count only means something attached to a named organism and amount.
For VAT, HMRC treats dietary supplements in tablet or capsule form as standard-rated at 20%.[13]
Product details on this page, including count (450 billion CFU per sachet), strain codes (NCIMB 30435 to 30442), per-strain counts, pack size (12 sachets of 4.4g), storage (+2°C to +8°C, up to 7 days at or below 25°C per the manufacturer's leaflet) and shelf life (18 months from manufacture, refrigerated), were verified by Probiotic.co.uk against the current UK pack label and the manufacturer's published product information (EOS2021 S.r.l., cds22.com). The price is shown on the product page, inc. 20% VAT. Always check the current label before use, as specifications can change.
The research discussed in this article relates to how live cultures are counted, labelled and studied in general. It should not be read as a claim that CDS22-formula, or any product, produces a health effect because of its CFU count. CDS22-formula is a food supplement, not a medicine. No authorised UK health claim is made for CDS22-formula or any of its strains on this page.
CDS22-formula Probiotic: 450 billion CFU, 8 NCIMB strains
Count stated to the best-before date under refrigeration. Cold-chain dispatched across the UK from our Lancashire facility.
Food supplement, not a medicine. Price shown on the product page, inc. 20% VAT. Probiotic.co.uk is the authorised UK distributor of CDS22-formula.
Frequently asked questions
What does CFU mean in probiotics?
CFU stands for colony-forming units. It is a laboratory estimate of how many live microorganisms in a serving can multiply into visible colonies on a culture plate. On a probiotic label it states quantity per serving, not which strains are present or what they do. The ISAPP consensus (Hill et al., Nature Reviews Gastroenterology & Hepatology, 2014, PMID 24912386) holds that effects should be read against specific strains at the amounts studied.
What does 450 billion CFU mean?
450 billion CFU means an estimated 450,000,000,000 viable colony-forming units per serving, written 4.5 × 10¹¹ in scientific notation, which is not necessarily the same as 450 billion individual cells. The total is a sum of the strains in the product, so the strain list matters as much as the number. For example, CDS22-formula's 450 billion per sachet is made up of eight NCIMB-coded strains, with 226 billion from Streptococcus thermophilus NCIMB 30438.
Can two probiotics with the same CFU count be different?
Yes. CFU states quantity only, so two products with the same count can contain entirely different species and strains, with different research behind them. A count also says nothing about whether it applies at manufacture or to the best-before date. Compare strain names and deposit codes, the count-to-date, and whether those strains were studied at that amount.
Is a higher CFU probiotic better?
Not as a general rule. A review of human dose-response studies (Ouwehand, Beneficial Microbes, 2017, PMID 28008787) found a dose-response for some endpoints but not for most. Effects are strain-specific, so a higher count only matters when that formulation was studied at that amount. A higher CFU is a specification, not evidence of greater benefit.
How many CFU should a probiotic have?
There is no single correct number, and Great Britain sets no general minimum CFU or recommended daily amount for food supplements. Italy's Ministry of Health uses a minimum of 1 × 10⁹ CFU per day for products described as probiotic, as recorded in the ISAPP consensus (Hill et al., 2014). The more useful test is whether the product's strains, at that amount, were used in published research.
What is the difference between CFU at manufacture and CFU at best-before?
A count at manufacture is measured when the product is made and does not account for the natural decline of live cultures over shelf life. A count to best-before is the minimum the manufacturer states will remain if the product is stored as directed. The ESPGHAN position paper (Kolaček et al., 2017, PMID 28644359) stresses that organisms must be present in sufficient number by the end of shelf life, so the best-before figure is the one to compare.
What is the difference between AFU and CFU?
CFU comes from plate counting and measures cells that can grow into colonies. AFU, active fluorescent units, comes from flow cytometry under ISO 19344:2015 and measures cells with intact, active membranes. Fresh cultures usually give similar figures, but AFU can read higher than CFU as a product ages, so the two should not be compared as if they were the same number.
Does the CFU count in a probiotic drop over time?
Yes. Live cultures decline gradually, and heat, moisture and oxygen speed this up, which is why the storage conditions on a label are part of the count claim. A Newcastle University study (Taha et al., Microorganisms, 2025, PMID 40871437) found all 12 UK probiotic products tested deviated from their labelled counts, and one of the five human products contained no detectable viable bacteria. Eleven of the 12 were within the study's practical ±0.5 log benchmark, and products were not named, so the study cannot be used to judge any individual brand.
Do high-CFU probiotics need to be refrigerated?
It depends on the product, not the count. Some formulations are refrigerated and some are shelf-stable, and both are fine if stored as their label directs. For a refrigerated product, the label count assumes it was kept cold, so cold-chain handling matters. CDS22-formula is stored at +2°C to +8°C, with up to 7 days at or below 25°C allowed by the manufacturer's leaflet.
Are high-CFU probiotics legal in the UK?
Yes. Probiotic supplements are sold legally in the UK as food supplements, subject to food, labelling and claims rules overseen by the Food Standards Agency, and CFU is a normal label specification. They are not medicines and are not licensed by the MHRA. In Great Britain no health claim is authorised for any probiotic strain, and Northern Ireland follows separate arrangements under the Windsor Framework, so a CFU figure can be stated as a specification but not presented as a benefit.
Where can I buy a 450 billion CFU probiotic in the UK?
CDS22-formula, with 450 billion CFU per sachet across 8 NCIMB-coded strains, is available from Probiotic.co.uk, the authorised UK distributor, with refrigerated cold-chain delivery across the UK including Northern Ireland. It is dispatched from a UK facility, so there are no import customs charges. It is a food supplement, not a medicine. See the product page for the current price and pack options.
- CFU (colony-forming unit) is a laboratory count of live microorganisms able to form colonies on a culture plate.
- CFU is not a measure of benefit. It states quantity per serving, not strain identity or effect.
- 450 billion CFU is an estimated 4.5 × 10¹¹ viable colony-forming units per serving, not a head count of individual cells.
- Great Britain sets no general minimum CFU for food supplements and no recommended daily amount. Italy's regulatory minimum is 1 × 10⁹ CFU per day (Hill et al., 2014, PMID 24912386).
- A count to best-before is more useful than a count at manufacture; organisms must be present in sufficient number by the end of shelf life (Kolaček et al., ESPGHAN, 2017, PMID 28644359).
- Human dose-response evidence is endpoint-specific, not general (Ouwehand, 2017, PMID 28008787).
- In a Newcastle University study of 12 UK probiotic products, measured counts differed statistically from labels; 11 were within a ±0.5 log benchmark and one of five human products had no detectable viable bacteria (Taha et al., 2025, PMID 40871437).
- AFU (flow cytometry, ISO 19344:2015) is an alternative live-cell count and is not interchangeable with CFU.
- In the UK, probiotics are food supplements under UK food law (FSA), not medicines. In Great Britain no probiotic health claim is authorised; Northern Ireland follows separate arrangements under the Windsor Framework.
- CDS22-formula Probiotic (450 billion CFU per sachet, 8 NCIMB strains, count stated to best-before under refrigeration) is available from Probiotic.co.uk with UK cold-chain delivery.
Related guides
This guide was prepared by Probiotic.co.uk using the following process:
- Reviewed the primary sources: the ISAPP consensus (Hill et al., 2014), the ESPGHAN quality-control position paper (Kolaček et al., 2017), the Ouwehand (2017) dose-response review, the Newcastle University UK label-accuracy study (Taha et al., 2025), ISO 19344:2015 and the EFSA 2010 live yoghurt cultures opinion.
- Kept laboratory measurement, labelling and regulation separate from any health outcome throughout.
- Verified every PMID against PubMed before publishing.
- Checked UK rules: the FSA food supplement framework, the DHSC position on the term "probiotic" (UK Parliament written answer HL899, 2024) and ASA/CAP probiotic claims guidance, treating Great Britain and Northern Ireland separately.
- Verified CDS22-formula strain codes, per-strain counts, storage and shelf life against the live UK product listing, pack label wording and the manufacturer's published product information.
- Checked the VAT treatment of supplements against HMRC VAT Notice 701/14.
- Made no health claim for any CFU count or product.
This guide is for educational purposes only and does not constitute medical advice. CDS22-formula is a food supplement and is not intended to diagnose, treat, cure, or prevent any disease or medical condition. It is not a medicine. The NHS recommends seeing a GP if digestive symptoms persist for more than 3 weeks. Probiotic.co.uk is regulated under UK food supplement legislation.
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. Nat Rev Gastroenterol Hepatol. 2014;11(8):506-514. PMID 24912386. DOI: 10.1038/nrgastro.2014.66. — https://pubmed.ncbi.nlm.nih.gov/24912386/
- Ouwehand AC. A review of dose-responses of probiotics in human studies. Benef Microbes. 2017;8(2):143-151. PMID 28008787. DOI: 10.3920/BM2016.0140. — https://pubmed.ncbi.nlm.nih.gov/28008787/
- Kolaček S, Hojsak I, Berni Canani R, et al. Commercial Probiotic Products: A Call for Improved Quality Control. A Position Paper by the ESPGHAN Working Group for Probiotics and Prebiotics. J Pediatr Gastroenterol Nutr. 2017;65(1):117-124. PMID 28644359. DOI: 10.1097/MPG.0000000000001603. — https://pubmed.ncbi.nlm.nih.gov/28644359/
- Taha MW, Fenwick DJC, Marrs ECL, Chaudhry AS. Assessing Bacterial Viability and Label Accuracy in Human and Poultry Probiotics Sold in the United Kingdom. Microorganisms. 2025;13(8):1933. PMID 40871437. DOI: 10.3390/microorganisms13081933. (Correction published: Microorganisms. 2026;14(3):607.) — https://pubmed.ncbi.nlm.nih.gov/40871437/
- ISO 19344:2015. Milk and milk products: Starter cultures, probiotics and fermented products. Quantification of lactic acid bacteria by flow cytometry. International Organization for Standardization. — https://www.iso.org/standard/64658.html
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to live yoghurt cultures and improved lactose digestion (ID 1143, 2976). EFSA Journal. 2010;8(10):1763. — https://efsa.europa.eu/en/efsajournal/pub/1763
- International Scientific Association for Probiotics and Prebiotics (ISAPP). Exploring resources to inform probiotic recommendations: New UK Probiotic Guide Released. 2025. — https://isappscience.org/exploring-resources-to-inform-probiotic-recommendations-uk-probiotic-guide/
- UK Parliament. Written question HL899: probiotics, answered by the Department of Health and Social Care. 2024. — https://questions-statements.parliament.uk/written-questions/detail/2024-09-09/HL899/
- Advertising Standards Authority / Committee of Advertising Practice. Food: Probiotic claims. — https://www.asa.org.uk/advice-online/food-probiotic-claims.html
- Food Standards Agency. Food supplements: business guidance. — https://www.food.gov.uk/business-guidance/food-supplements
- EOS2021 S.r.l. CDS22-formula 450 billion live bacteria sachet: product information and ingredients (UK site). — https://cds22.com/gb/products/450-billion-live-bacteria-sachet/
- EOS2021 S.r.l. CDS22-formula 450 billion live bacteria sachet: storage information. — https://cds22.com/en/products/450-billion-live-bacteria-sachet/
- HM Revenue & Customs. Food products (VAT Notice 701/14), section on dietary supplements. — https://www.gov.uk/guidance/food-products-and-vat-notice-70114