Because of its unique composition and chemical properties, honey is suitable for long-term storage, and is easily assimilated even after long preservation. Honey, and objects immersed in honey, have been preserved for centuries.The key to preservation is limiting access to humidity. In its cured state, honey has a sufficiently high sugar content to inhibit fermentation. If exposed to moist air, its hydrophilic properties pull moisture into the honey, eventually diluting it to the point that fermentation can begin.
The shelf life of honey is due to an enzyme found in the stomach of bees. Glucose oxidase is mixed by the bees with expelled nectar previously consumed by the bees which then creates “two by-products: gluconic acid and hydrogen peroxide” which are responsible for honey’s acidity and ability to suppress bacterial growth.
Source: Ultra Facts