TA70+ Honey, TA35+, MGO and UMF™: How Antibacterial Activity in Honey Is Actually Measured
1. The Industry-Standard Test for Antibacterial Activity
If you are searching for:
- Is TA70+ honey real?
- What is TA vs MGO?
- How is antibacterial activity in honey measured?
- What does UMF™ actually mean?
- Are TA, NPA and MGO grading systems?
This article explains the science.
Because much of the confusion online comes from misunderstanding what these measurements actually represent.
In Australia and New Zealand, the commercial and research-standard test for quantifying antibacterial activity in honey is the phenol equivalence assay.
This assay has also historically been referred to as the UMF assay.
It is used by:
- Commercial laboratories
- NATA-accredited facilities
- Academic researchers
- Peer-reviewed studies
How the Phenol Equivalence (PE) Assay Works
The assay is an agar diffusion method:
- A 25% honey solution is prepared.
- Wells are cut into nutrient agar seeded with Staphylococcus aureus ATCC 25923.
- Honey solutions are added to the wells.
- A series of phenol standards are run alongside.
- After incubation, inhibition zones are measured.
- Honey activity is compared to the phenol standard curve.
- A phenol equivalence (PE) value is assigned.
This produces a percentage equivalence to phenol.
2. What TA and NPA Actually Mean
TA and NPA are not grading systems.
They are measurements.
TA (Total Activity)
Measures overall antibacterial activity (peroxide + non-peroxide).
NPA (Non-Peroxide Activity)
Measures antibacterial activity after hydrogen peroxide has been removed using catalase.
NPA isolates the non-peroxide component of antibacterial activity.
In Leptospermum honeys (e.g., Manuka), this non-peroxide activity is strongly associated with methylglyoxal (MGO).
3. What MGO Actually Measures
MGO is not antibacterial activity.
MGO is the concentration (mg/kg) of methylglyoxal in the honey.
It is a chemical quantification, not a biological assay.
However, research shows a strong positive linear correlation between MGO concentration and non-peroxide activity in Leptospermum honeys.
The relationship follows approximately:
- MGO <260 mg/kg → NPA <10%
- MGO ~260–800 mg/kg → NPA 10–20%
- MGO >800 mg/kg → NPA >20%
This correlation explains why MGO became commercially important.
But MGO itself is not a direct measure of antibacterial performance – it is a marker correlated to NPA.
4. Broad Approximate Equivalencies Between Systems
Industry broadly accepts approximate equivalencies:
Unique Manuka Factor | Methylglyoxal | Non-Peroxide Activity | Total Activity |
UMF™ | MGO | NPA | TA |
A trademark restricted to New Zealand producers based on MGO, Leptosperin & DHA. | Concentration of an active non peroxide component in honey. | Antibacterial potency that is not derived from hydrogen peroxide. | Antibacterial potency that is derived from hydrogen peroxide + non peroxide components. |
5+ | 83 | 5+ | 5+ |
10+ | 263 | 10+ | 10+ |
15+ | 514 | 15+ | 15+ |
20+ | 829 | 20+ | 20+ |
25+ | 1202 | 25+ | 25+ |
30+ | 1625 | 30+ | 30+ |
35+ | 2001 | 33+ | 35+ |
These are approximations, not exact conversions.
Different systems measure different things:
- UMF™ – trademarked New Zealand grading system incorporating MGO, DHA, leptosperin
- MGO – chemical concentration
- NPA – biological non-peroxide activity
- TA – total antibacterial effect
They are not interchangeable scales.
5. Why Australian Laboratories Report TA35+
Under the phenol equivalence assay:
- Activity is plotted against phenol standards.
- The assay has validated calibration limits.
- Reporting precision is standardised.
Under Australian laboratory protocols – including those used by NATA-accredited laboratories – antibacterial activity above a defined threshold is reported as “35+”.
This reflects the upper validated reporting range of the assay.
Laboratories do not issue certified reports stating TA70+ under the standard phenol equivalence method.
This does not mean higher antibacterial potency cannot exist.
It means the validated reporting method caps precision at TA35+.
6. Why TA70+ Claims Create Confusion
When consumers see TA70+, important questions include:
- Was phenol equivalence methodology used?
- Was the assay validated?
- Was the lab NATA-accredited?
- Is a certificate available?
- Is the number derived from biological assay or extrapolated?
Scientific credibility depends on:
Using validated methods.
Respecting reporting limits.
Distinguishing between measurement and marketing.
7. Key Clarifications for Consumers
TA, NPA and MGO are measurements – not “grades.”
MGO quantifies a chemical marker.
TA and NPA measure biological antibacterial performance.
UMF™ is a trademarked commercial system incorporating multiple markers.
TA35+ represents extremely high antibacterial activity under validated phenol equivalence methodology.
Certified Australian laboratory reports are limited to TA35+ under this system.
8. Why This Matters
Across Australia, the UAE and Saudi Arabia, consumers are increasingly:
- Research-driven
- Comparing MGO vs TA
- Searching for highest antibacterial honey
- Evaluating clinical credibility
Understanding the assay methodology prevents:
- Misinterpretation
- Incomparable claims
- Inflated expectations
- Category confusion
9. The Scientific Standard
The phenol equivalence assay was first described in 1991 in “A survey of the antibacterial activity of some New Zealand honeys.” Since then it has consistently been described and validated in scientific studies for over 30 years.
It remains the commercial standard across Australia and New Zealand.
Conclusion
If you are searching for:
“Is TA70+ honey real?”
“What is higher than TA35?”
“Is TA better than MGO?”
The answer lies in understanding the assay.
TA35+ represents the upper validated reporting range under recognised phenol equivalence testing.
Scientific integrity means reporting results as laboratories issue them – not extending numbers beyond validated limits.
Because precision matters.
And in antibacterial honey, methodology defines credibility.
References
- Molan P. Improvements to the UMF assay. New Zealand BeeKeeper. 2008; 16(7):24–5.
- Chen C, Campbell LT, Blair SE, Carter DA. The effect of standard heat and filtration processing procedures on antimicrobial activity and hydrogen peroxide levels in honey. Front Microbiol. 2012; 3:265.
PMID: 22866051 - Cokcetin NN, Pappalardo M, Campbell LT, Brooks P, Carter DA, Blair SE, et al. The antibacterial activity of Australian Leptospermum honey correlates with methylglyoxal levels. PLoS One. 2016; 11(12): e0167780. PMID: 28030589
- Allen KL, Molan P, Reid GM. A survey of the antibacterial activity of some New Zealand honeys. J Pharm Pharmacol. 1991; 43(12):817–22. PMID: 1687577
- Irish J, Blair S, Carter DA. The antibacterial activity of honey derived from Australian flora. PLoS One. 2011; 6(3):e18229. PMID: 21464891
- Girma A, Seo W, She RC. Antibacterial activity of varying UMF-graded Manuka honeys. PLoS One. 2019; 14(10):e0224495. PMID: 31652284
- Tsang AS, Dart AJ, Sole-Guitart A, Dart CM, Perkins NR, Jeffcott LB. Comparison of the effects of topical application of UMF20 and UMF5 manuka honey with a generic multifloral honey on wound healing variables in an uncontaminated surgical equine distal limb wound model. Aust Vet J. 2017; 95(9):333–7. PMID: 28714567
- Green KJ, Dods K, Hammer KA. Development and validation of a new microplate assay that utilises optical density to quantify the antibacterial activity of honeys including Jarrah, Marri and Manuka. PLoS One. 2020 Dec 9;15(12):e0243246. PMID: 33296391; PMCID: PMC7725308.
- Cokcetin NN, Pappalardo M, Campbell LT, Brooks P, Carter DA, Blair SE, Harry EJ. The Antibacterial Activity of Australian Leptospermum Honey Correlates with Methylglyoxal Levels. PLoS One. 2016 Dec 28;11(12):e0167780. PMID: 28030589; PMCID: PMC5193333.
