When you evaluate an Akkermansia muciniphila ingredient, the potency number on the spec sheet only means something if you know which unit it is expressed in. Unlike conventional probiotics, which are typically quantified in CFU (colony-forming units), Akkermansia is an obligate anaerobe that is difficult to culture on standard plate counts — so the industry increasingly quantifies it by flow cytometry, using fluorescent units rather than colony counts.
That shift creates a practical problem for R&D, QA, and regulatory teams: two different fluorescent-unit systems are in circulation, and they are not interchangeable. Reading one as the other can lead to a mislabeled dose, an off-target specification, or a finished product that does not match its regulatory basis.
Quick Answer
AFU and TFU are two different flow-cytometry measurements of Akkermansia cell count, and they are not interchangeable. AFU (Active Fluorescent Units) counts cells with intact, metabolically active membranes and is the unit used for GRAS dosage — covering both live and pasteurized forms for food use. TFU (Total Fluorescent Units) counts total cells regardless of membrane activity and is the unit used for NDI dosage — which applies to the pasteurized (postbiotic) form only.
For AKK PROBIO (Akkermansia muciniphila CGMCC No.20955): the GRAS use level is expressed in AFU (≤ 7.0×10¹⁰ AFU per serving; ≤ 1.3×10¹² AFU per day for a 70 kg adult), while NDI #1468 is expressed in TFU (170 mg/day = 3.4×10¹⁰ TFU/day). Do not convert one into the other, and do not carry a number from one regulatory context into the other.
Why Akkermansia Uses Fluorescent Units Instead of CFU
CFU measures how many cells form colonies on a plate. That works well for robust, easily cultured lactic-acid bacteria, but it undercounts or misrepresents organisms that are hard to culture — and Akkermansia muciniphila is a strict anaerobe with specific growth requirements.
Flow cytometry offers a more direct count: cells are stained with fluorescent dyes and counted individually as they pass through a detector. Depending on the dye and gating strategy, the instrument can distinguish between cells with intact, active membranes and the total cell population. That distinction is exactly where AFU and TFU come from.
For a buyer, the practical takeaway is that a fluorescent-unit potency is not a "weaker" measure than CFU — it is a more appropriate one for this organism. The key is knowing which fluorescent unit is on the document in front of you.
AFU (Active Fluorescent Units): The GRAS Unit
AFU counts the subpopulation of cells whose membranes are intact and metabolically active — in plain terms, the cells that are functionally "alive" at the time of measurement.
AFU is the unit tied to AKK PROBIO's self-affirmed GRAS status under 21 CFR §170.30, which covers both the live (probiotic) and pasteurized (postbiotic) forms for conventional food use:
- Per serving: ≤ 7.0×10¹⁰ AFU
- Per day (70 kg adult): ≤ 1.3×10¹² AFU
When you are formulating a food or beverage under the GRAS route, AFU is the number that belongs in your specification and your dose rationale.
TFU (Total Fluorescent Units): The NDI Unit
TFU counts the total cell population detected by the instrument, without gating on membrane activity. It is therefore always equal to or greater than the AFU count for the same sample.
TFU is the unit tied to AKK PROBIO's FDA New Dietary Ingredient Notification #1468, which covers the pasteurized (postbiotic) form only for dietary supplement use:
- Maximum daily intake: 170 mg/day = 3.4×10¹⁰ TFU/day
- Population: healthy adults 18+; excludes pregnant and lactating women
Because NDI #1468 applies only to the pasteurized form, TFU appears specifically in the pasteurized-form dietary-supplement context. It is not the unit for the live form, and it is not the unit for the GRAS food route. The NDI notification has been covered independently by industry media — see Nutritional Outlook's report for a third-party account of the filing and its conditions of use.
Side-by-Side: AFU vs. TFU
| Dimension | AFU (Active Fluorescent Units) | TFU (Total Fluorescent Units) |
|---|---|---|
| What it counts | Cells with intact, active membranes | Total detected cell population |
| Regulatory context | GRAS (food use) | NDI #1468 (dietary supplements) |
| Forms covered | Live + pasteurized | Pasteurized (postbiotic) only |
| AKK PROBIO level | ≤ 7.0×10¹⁰ AFU/serving; ≤ 1.3×10¹² AFU/day | 170 mg/day = 3.4×10¹⁰ TFU/day |
| Relative magnitude | Smaller (subset of total) | Larger (includes AFU population) |
| Interchangeable? | No | No |
The Three Mistakes We See Buyers Make
1. Treating AFU and TFU as the same number. Because TFU counts the total population and AFU counts the active subset, a TFU figure is always numerically higher than the AFU figure for the same material. Comparing two suppliers where one quotes AFU and the other quotes TFU — without noticing — is comparing apples to oranges.
2. Carrying a number across regulatory contexts. A GRAS dose expressed in AFU cannot be restated as a TFU figure for an NDI supplement, and vice versa. The two rest on different regulatory bases with different use conditions. Moving a number from one to the other breaks the documentation chain your QA and regulatory teams rely on.
3. Not asking which unit the COA uses. A certificate of analysis that reports a fluorescent-unit count without naming the unit leaves the most important question unanswered. Always confirm whether a reported potency is AFU or TFU before you write it into a specification.
What to Request From Your Supplier
When you review an Akkermansia ingredient, ask for the unit to be stated explicitly and consistently across every document:
- The specification should name the unit (AFU or TFU) next to the potency value.
- The COA should report results in the same unit, lot by lot.
- The regulatory documentation should make clear which unit underpins which pathway — AFU for GRAS, TFU for NDI — and which form each covers.
AKK PROBIO is quantified by flow cytometry and standardized so that the unit matches the regulatory route: AFU for GRAS food applications, TFU for the NDI dietary-supplement pathway. Our distribution partner Maypro standardizes the live form by AFU and the pasteurized form accordingly, so the documentation stays consistent from ingredient to finished product. See Maypro's AKK PROBIO product page for how the dual standardization is described.
Getting the Dose Right for Your Formulation
Dosage units are a small detail that carries real regulatory and labeling weight. If you are scoping an Akkermansia project and want the specification, COA format, and regulatory package that match your intended route — GRAS food or NDI supplement — we can walk you through the documentation. Request a sample or review our Regulatory & Safety page for the full status of each form.