水分活度（Aw）与食品防腐

水分活度是食品中水的蒸气压与同温下纯水的蒸气压之比，用符号Aw表示。近来的研究证明，它与食品的保鲜质量关系密切。食品中的水活性可以影响食品中微生物的繁殖，代谢，抗性及生存等。控制食品水活度，再辅以其它保鲜措施，可以有效提高食品的货架期。

Water Activity and Preservation of Food

Water activity, denoted by the symbol Aw, is the ratio of vapour pressure in food to the vapour pressure of pure water at the same temperature. Recently studies have shown that the water activity has a close relationship with food preservation. The water activity in food may inflence reproduction, metabolism, preservation and existence of microorganisms in food. Controlling the water activity in food and adopting auxiliary measures of food preservation may effectively prolong the shelf life of food.