Why not pasteurize honey?
Honey will deteriorate when exposed to heat. The higher the heat, the faster and greater the effect. For example, honey has numerous enzymes. Most of these enzymes remain stable under 100ºF but have decreased activity when exposed to temperatures over 120ºF. For instance, the enzyme diatase, which is common in honey, shows a 50% reduction in activity after 15 days at 122ºF. Most enzymes in honey are almost completely destroyed when exposed to temperatures above 160ºF for even a short period. These enzymes are also destroyed when honey is liquified in a micro wave oven. An interesting side note is that most of the enzymes in honey are added by the bees.
