The MGO lettering is the shorthand for ‘Methylglyoxal’, the dominant active component in Mānuka honey, used to measure anti-bacterial activity. Labels with MGO (plus a number) explain the presence of Methylglyoxal in the content. The minimum for a monofloral Mānuka honey is MGO 83. The higher the number, the higher the MGO level.
Measuring only one compound, such as MGO, is not sufficient to ensure that compound is from a natural Mānuka honey source. That's why Comvita adopts a dual grading system - MGO & UMF™ to provide additional assurance to consumers.
UMF™ stands for Unique Manuka Factor, an independently certified quality assurance mark for genuine New Zealand monofloral Mānuka honey. UMF™ measures both the purity and quality of manuka honey based on the levels of three unique signature compounds: leptosperin, dihydroxyacetone (DHA), and methylglyoxal (MGO).
Methylglyoxal (MGO) is responsible for the unique non-peroxide antimicrobial activity of Mānuka honey (Adams 2008, Mavric 2008), it forms from DHA in manuka honey as it matures (Adams 2009). Leptosperin and DHA are naturally occurring compounds found in Mānuka nectar and thus are present in Mānuka honey (Adams 2009, Bong 2017). These three signature compounds together indicate high quality, authentic Mānuka honey.
The UMF™ grade of Mānuka honey corresponds to its non-peroxide antimicrobial property. Mānuka honey with a UMF™ rating of 10+ has a non-peroxide antimicrobial property equivalent to that of a control 10% phenol solution. A higher UMF™ rating indicates higher non-peroxide antibacterial property of the Mānuka honey
What about other grading systems?
KFactor™ , Molan Gold measure multiple non-specific Mānuka honey components, which are not sufficient to ensure that compound is from a natural Mānuka honey source.