The key things when you’re purchasing Mānuka honey is to always look at the label. On the label, it will have either a UMF™ number which will be from 5 up to maybe as high as 20 or even 24. When it has UMF, that is a quality standard that is in place to ensure that the honey meets and has been tested.
The MGO number that is sometimes also seen on a pack of Mānuka honey is a similar thing, but it isn’t regulated as closely as the UMF™ number. The UMF™ is checked from shelves all around the world to make sure that, that honey in those jars meets that level of antibacterial activity.