AFU vs CFU in Probiotics: Why Akkermansia Labels Use a Different Number

You spot 500 million AFU on an Akkermansia supplement, but the probiotics you know usually say CFU. Do the letters mean the same thing?

Not quite. The letters tell you how microorganisms were measured. At Healthy, we stock CODEAGE Akkermansia 500 Ultra, a synbiotic labelled with 500 million AFUs of a named Akkermansia strain per serving.

CFU means colony-forming units. It estimates microorganisms able to grow into colonies under specified laboratory conditions. AFU means Active Fluorescent Units. This is generally measured using fluorescence-based flow cytometry, which counts cells meeting defined activity or viability criteria. Because the methods ask different questions, an AFU figure cannot automatically be converted into an equivalent CFU figure.

First, imagine a laboratory growing bacterial colonies

For a CFU count, a laboratory places a sample onto suitable growth medium under defined conditions. It counts colonies that grow and estimates the colony-forming units in the original sample.

The method is well established, but not every viable organism will grow under the chosen conditions. A colony can also begin from a cluster of cells, rather than one individual cell.

CFU therefore measures colony-forming ability under those conditions, not every living cell in the sample. For broader label advice, see our guide to probiotic supplements in NZ.

Now imagine counting cells by their fluorescent signals

AFU takes another approach. In fluorescence-based flow cytometry, cells pass through an instrument that detects light signals. Fluorescent markers help distinguish cells by their characteristics without waiting for colonies to form.

The markers might indicate an intact cell membrane or signs of enzyme activity. Which cells count as active depends on the staining method and its criteria.

AFU is not a universal headcount of every living cell. The ISO 19344:2015 flow-cytometry standard covers certain lactic acid bacteria and dairy-related products; it does not certify CODEAGE Akkermansia AH39.

Think of the difference this way: CFU asks which microorganisms formed colonies in the test. AFU asks which cells met selected criteria revealed by fluorescent signals.

Why these two counts do not translate into each other

Two laboratories might test the same microorganism, one counting colonies and the other fluorescent signals, and report different results. The organism, storage, culture conditions and staining rules all influence what gets counted.

Some cells retain signs of viability but do not grow in a particular culture test. That does not prove they will grow in your gut, establish themselves or produce a benefit.

There is no universal AFU-to-CFU conversion formula. Five hundred million AFU is not automatically five hundred million CFU. Nor can you judge it against an unrelated probiotic labelled with billions of CFU as though both numbers came from the same test.

A 2026 Journal of AOAC International study found reasonable agreement between the methods for Lacticaseibacillus rhamnosus in a snack product. It did not test Akkermansia AH39 or establish a universal conversion formula.

Both methods tell us something valuable about a sample. Neither unit alone demonstrates that taking a supplement will produce a health benefit.

So why might an Akkermansia label use AFU?

Akkermansia muciniphila is a strictly anaerobic bacterium. In simple terms, it is adapted to an environment without oxygen. Growing and counting it can require specialised laboratory conditions, which is one reason a fluorescence-based measurement may be useful for an Akkermansia preparation.

This does not mean Akkermansia cannot be grown or counted using CFU. It can be cultured under suitable conditions. AFU is simply another way of assessing a defined cell population, with different strengths and limitations.

Knowing the method helps you read an Akkermansia label without comparing unrelated numbers.

What 500 million AFU means on our CODEAGE Akkermansia 500 Ultra

We like being able to show you exactly which organism sits behind the number. Our CODEAGE Akkermansia 500 Ultra product details identify Akkermansia muciniphila AH39 and declare 500 million AFUs per serving.

That 500 million is the stated AFU amount for AH39. It is not a claim of 500 million colony-forming units. And the 500 in the product name does not mean 500mg of Akkermansia.

Our listing separately gives 150mg of Akkermansia ingredient and 276mg of chicory inulin. Milligrams describe mass. AFUs describe cells meeting specified fluorescence-based criteria. You cannot use the weight to calculate an equivalent number of active cells.

We want every number to make sense. With a named strain, a declared AFU quantity and the ingredient details, you have something specific to explore when looking for an Akkermansia supplement in NZ.

The detail that changes the meaning of a count over time

A microbial count can change as a supplement is stored. So the point in time attached to a number matters, whether the number is written in AFU or CFU. A count stated at manufacture is not the same promise as one stated at expiry.

This timing is separate from the measurement method. AFU does not automatically mean an expiry count, and CFU does not automatically mean a manufacture count.

For transparency, our current CODEAGE Akkermansia 500 Ultra listing says its AFU count is measured at manufacture, while CODEAGE's current manufacturer information says at expiry. Those details do not agree. Until the current pack or supplier specification confirms the wording, we would not treat the 500 million AFU declaration as a verified expiry-time guarantee. You can ask our team to help clarify the label on the available product.

There's more inside the capsule than the AFU number

CODEAGE Akkermansia 500 Ultra is not simply a number on a label. It combines the AH39 strain with chicory inulin, a prebiotic fibre from chicory root. Including a bacterial ingredient and a prebiotic makes this a synbiotic formula.

We also like the format: one enteric-coated vegetarian capsule per adult serving and 90 capsules per bottle. The coating is designed to help protect the contents during digestion, but does not guarantee survival or gut colonisation.

The formula is also listed as vegan, non-GMO, dairy-free, soy-free and gluten-free.

What does this mean when you're considering an Akkermansia supplement?

Five hundred million AFU and billions of CFU are not scores from the same test. They may describe entirely different strains and formulations.

We appreciate the clear focus on AH39, its stated AFU quantity, chicory inulin and the one-capsule format. It is worth exploring.

A quick safety note: This is a food supplement, not a treatment for disease or weight reduction. Adults should follow the listed one-capsule-daily directions or their healthcare professional's advice and should not exceed the recommended amount. Check ingredients if you have allergies or sensitivities. Seek medical advice first if you are pregnant, breastfeeding, under 18, have a known medical condition, are immunocompromised, are seriously unwell or take medicines. Keep it away from children and pets, and do not use it if the safety seal is missing or damaged.

Explore the latest ingredients and purchase options below.

Common questions about AFU and CFU

What does AFU mean on a probiotic supplement?

AFU stands for Active Fluorescent Units. It describes cells counted using a fluorescence-based method and specified criteria linked with activity or viability, such as membrane integrity. The result depends on the test method. It is not an exact, universal count of every living cell.

What is the difference between AFU and CFU?

CFU, or colony-forming units, estimates microorganisms able to form colonies under particular culture conditions. AFU, or Active Fluorescent Units, counts cells that meet specified fluorescence-based criteria. One measures colony-forming capacity; the other assesses selected cell characteristics. They are not interchangeable units.

Is 500 million AFU the same as 500 million CFU?

No. A declaration of 500 million AFU is not automatically equivalent to 500 million CFU. Different test methods can count different cell populations, even in the same sample. The two figures should not be compared as though they are identical measures.

Can AFU be converted into CFU?

There is no universal conversion formula. Researchers can examine how AFU and CFU counts relate for a particular microorganism, preparation and validated testing approach. That relationship cannot simply be transferred to every probiotic, including Akkermansia AH39.

Why does Akkermansia use AFU instead of CFU?

Akkermansia is a strictly anaerobic microorganism that needs suitable conditions to grow in the laboratory. Some Akkermansia preparations use fluorescence-based counting to assess cells meeting defined activity or viability criteria. That does not mean Akkermansia is impossible to culture or that AFU is automatically superior.

Does a higher AFU count mean a better probiotic?

Not necessarily. A larger AFU quantity does not by itself prove a greater health benefit. The organism, strain, preparation, formulation and evidence for that specific product all matter. AFU helps describe a measured quantity, not a guaranteed result after taking the supplement.

What does 500 million AFU mean on CODEAGE Akkermansia 500 Ultra?

It means the product declares 500 million Active Fluorescent Units of Akkermansia muciniphila AH39 per labelled serving. That figure is a fluorescence-based count, not 500 million CFU and not a milligram amount. The ingredient mass is listed separately.

Explore CODEAGE Akkermansia 500 Ultra at Healthy

AFU becomes easier to understand when you know what the test measures. CFU and AFU are both useful, but they do not mean the same thing.

We are pleased to offer CODEAGE Akkermansia 500 Ultra for New Zealand customers interested in a clearly identified AH39 strain, a declared 500 million AFU quantity and a synbiotic formula with chicory inulin. Its enteric-coated vegetarian capsule keeps the daily format simple.

Explore the full product details at Healthy, check the current directions and precautions, and see whether this Akkermansia formula is the one you want to try.

References

• ISO 19344:2015, quantification of lactic acid bacteria by flow cytometry.
• Boyte et al. (2023), Probiotic and postbiotic analytical methods, Frontiers in Microbiology.
• Saiz-Gonzalo et al. (2026), Flow cytometry and plate count correlation, Journal of AOAC International.
• NIH Office of Dietary Supplements, Probiotics.
• Australian TGA, Akkermansia muciniphila ATCC BAA-835 (a different, pasteurised strain preparation).
• Medsafe, Regulation of Dietary Supplements.
• CODEAGE, Akkermansia 500 Ultra product information.