TA vs MGO: The Science of Testing High-Strength Bioactive Honey

How TA and MGO are Tested

To determine how effective a therapeutic honey is, scientists use completely different laboratory testing methods depending on whether they are measuring Total Activity (TA) or Methylglyoxal (MGO).

One relies on a dynamic biological test to see how well the honey actually kills bacteria,
while the other uses a chemical instrument to count specific molecules.

Here is exactly how scientists evaluate and calculate both ratings in the lab.

How Scientists Determine TA Rating:
(Total Activity)

Total Activity is measured using a microbiological assay (a live biological test). Instead of just looking for a chemical, scientists test the honey's real-world ability to stop live bacteria from growing.

The Lab Process: The Agar Well Diffusion Method

1. Preparing the Bacteria: Scientists coat a petri dish containing nutrient agar with a standardised strain of bacteria, typically Staphylococcus aureus (the bacteria responsible for golden staph and many skin infections).

2. Cutting the Wells: Small circular holes (wells) are punched into the agar plate.

3. Adding the Honey: Samples of the honey being tested are diluted with water (which activates the glucose oxidase enzyme) and placed into the wells.

4. The Control Solution: In separate wells on the same plate, scientists add varying percentage concentrations of pure phenol (a powerful industrial antiseptic) to act as a benchmark control (e.g., 10%, 20%, 30%, 35% phenol solution).

5. Incubation & Measurement: The plate is incubated at 37°C for 24 hours. As the honey's enzymes wake up and release hydrogen peroxide, they diffuse outward into the agar, killing the bacteria around the well. This leaves a clear ring of dead bacteria known as the Zone of Inhibition.

Calculating the Final TA Score

Scientists measure the diameter of the clear zone created by the honey and compare it directly to the zones created by the phenol solutions:

• If a honey creates a zone of cell death equal to a 20% pure phenol solution, it is awarded a rating of TA 20+.

• If it matches or exceeds the killing power of a 35% phenol solution, it is certified as TA 35+.

Because it measures the combined killing force of both the active hydrogen peroxide and any natural plant-based non-peroxide factors, it is called Total Activity.

How Scientists Evaluate Manuka MGO (Methylglyoxal)

Unlike the live bacterial testing used for TA, evaluating Manuka's MGO rating is a purely chemical testing process. It doesn't measure live bacterial death in a dish; instead, it counts the physical mass of the Methylglyoxal molecule present in the honey.

The Lab Process: HPLC (High-Performance Liquid Chromatography)

1. Extraction: A precise sample of Manuka honey is dissolved in a solvent to extract its organic compounds.

2. The HPLC Machine: The liquid sample is injected into a sophisticated instrument known as a High-Performance Liquid Chromatograph.

3. Separation: The machine pumps the liquid at incredibly high pressure through a specialised tube (column) packed with microscopic particles. Because different molecules move through this column at different speeds based on their size and chemical properties, they separate cleanly from one another.

4. Detection: As the separated molecules emerge from the column, a detector measures how much light they absorb at a specific wavelength, creating a digital peak on a graph.

Calculating the Final MGO Score

The size of the "MGO peak" on the laboratory graph tells scientists exactly how many milligrams of Methylglyoxal are packed into every single kilogram of honey.

• MGO 400+ means the lab instrument detected at least 400 mg of methylglyoxal per 1 kg of honey.

• MGO 2000+ means a massive 2000 mg (2 grams) of pure chemical methylglyoxal is present per 1 kg of honey.

By utilising live bacterial testing, a TA rating gives an exact real-time measurement of how effectively the honey functions when applied to tissue or consumed, whereas an MGO rating proves the chemical raw density of Manuka's primary active compound.

TA (Total Activity) vs NPA (Non Peroxide Activity)