十万个为什么·科学阅读30篇（2）

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为什么蜂蜜即使存放数千年也不会变质？

Archaeologists have found edible honey in ancient Egyptian tombs dating back over 3,000 years.
Its low water content—usually under 18%—makes it too dry for most microbes to reproduce.
Natural hydrogen peroxide forms slowly in honey when glucose oxidase enzyme reacts with oxygen and glucose.
High acidity (pH 3.2–4.5) further inhibits bacterial and fungal growth inside sealed containers.
Bees also fan nectar with wings to evaporate excess moisture before storing it in combs.
Crystallization does not indicate spoilage but rather a natural physical change in sugar structure.
Even if exposed briefly to air, honey resists contamination better than almost any other food.
Its antimicrobial properties have been used historically for wound dressings and preservation.
Modern labs confirm that spores of harmful bacteria like Clostridium botulinum cannot germinate in pure honey.
However, infants under one year should never consume it because their immature guts lack protective acid barriers.