Honey producers have a scale for rating the potency of manuka honey. UMF stands for Unique Manuka Factor · UMF identifies natural unadulterated manuka honey produced in New Zealand · UMF is the only manuka honey grading. The UMF (Unique Manuka Factor) rating number on every jar of Comvita represents the unique signature compounds characteristic of real Manuka Honey , which. What is UMF? UMF stands for “Unique Manuka Factor” and is a grading system developed by the UMF Honey Association in New Zealand. Manuka honey manufacturers label their product with a unique Manuka factor ( UMF) rating. The Unique Manuka Factor (UMF) grading system reflects the MGO concentration in Manuka honey sold commercially.