MGO is methylglyoxal (the antibacterial component in manuka).
Beware of manuka honey sold in Japan that does not indicate MGO content!
Some vendors use marketing talk that they cannot display MGO as defined by New Zealand's Ministry of Primary Industries.
Indeed, the current New Zealand Department of Primary Industries definition of manuka honey does not emphasize MGO content.
However, MGO content is not irrelevant. All manuka honeys, both monofloral and multifloral, contain MGO. However, MGO can be produced artificially. There was an incident in which a Chinese vendor was arrested for selling honey containing artificial MGO.
To combat counterfeit manuka, New Zealand's Department of Primary Industries has changed the definition of manuka. The current test now looks at 4 manuka markers (4 components) and 1 DNA .
The test identifies DNA that is unique to Manuka. Manuka honey approved by this test is a proof of authenticity.
As a result, it is no longer possible to say that manuka honey contains MGO, and counterfeit manuka can no longer be sold as manuka honey.
However, all Manuka contains MGO. MGO figures are properly displayed during inspections to obtain export licenses.
And the numbers indicate the concentration of antibacterial power of manuka honey.
MGO is irrelevant. Be careful of stores and vendors called. Perhaps the MGO value is very low, or it is not shown to hide the fact that it is not monofloral manuka. So don't be fooled by the marketing talk.