Water activity, aW, is a physical property that has a direct implication for microbiological safety of food. Water activity also influences the storage stability stability of foods as some deteriorative processes in foods are mediated by water. Storage life of dry foods such as biscuits is generally longer then of moist foods such as meat at the same temperature. In this connection freezing of foods is equivalent to drying the water is removed from the food matrix although it is still in the food as ice.
Because of this strong association between the physical property, aw, and the chemical and microbological properties of food, it is appropriate to include these aspects in the form of a Knowledge Base on this website.